LT1 w/ P&P heads Vs. LT4...
09-17-2013, 04:57 PM
#1
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Thread Starter
LT1 w/ P&P heads Vs. LT4... First off, I am wanting to drop a LT4 into a 1970 240z. That is my intent.
My question(s) is, since the main difference between the two (the LT1/LT4) is valve size and minor head design improvements, would porting and polishing the heads of an LT1 give me the same (if not better) results? Lt1 engines are much easier to find than Corvette LT4 engines, and I would want to P&P the heads no matter which one I find.
And can larger valves be put into LT1 heads (with the proper milling, etc)? People put larger valves into engines all the time, I do not see why it wouldnt be possible here.
My plan is to stay with the 350ci displacement, and just port/polish/blueprint/balance everything to make it as good as it should be. MSD ignition, LT4 "hotcam", Edelbrock intake/58mm TB's, Clear Image Tri-Y Impala SS headers (if they will fit in the Z-car). Chevy 350 engine, Chevy 350 transmission, 3.50 rear diff gears... with 350rwhp being my goal.
The Tri-Y headers help with lower RPM torque. And I have read about a good deal of milling that can be done to the heads/valves for low-valve-lift/low-RPM torque. This is not going to be a high-revving engine, so I want as much torque available as quickly as possible. And I want a nice smooth power curve for nice street manners. I want the car to drive smooth, I dont need anything fancy... its a 5.7L V8 going into a 2,000 pound car.
My question(s) is, since the main difference between the two (the LT1/LT4) is valve size and minor head design improvements, would porting and polishing the heads of an LT1 give me the same (if not better) results? Lt1 engines are much easier to find than Corvette LT4 engines, and I would want to P&P the heads no matter which one I find.
And can larger valves be put into LT1 heads (with the proper milling, etc)? People put larger valves into engines all the time, I do not see why it wouldnt be possible here.
My plan is to stay with the 350ci displacement, and just port/polish/blueprint/balance everything to make it as good as it should be. MSD ignition, LT4 "hotcam", Edelbrock intake/58mm TB's, Clear Image Tri-Y Impala SS headers (if they will fit in the Z-car). Chevy 350 engine, Chevy 350 transmission, 3.50 rear diff gears... with 350rwhp being my goal.
The Tri-Y headers help with lower RPM torque. And I have read about a good deal of milling that can be done to the heads/valves for low-valve-lift/low-RPM torque. This is not going to be a high-revving engine, so I want as much torque available as quickly as possible. And I want a nice smooth power curve for nice street manners. I want the car to drive smooth, I dont need anything fancy... its a 5.7L V8 going into a 2,000 pound car.
09-17-2013, 05:27 PM
#2
David
My comments
1. if you want a low RPM TQ monster, don't get the LT4 "hot" cam. It really makes its power in the upper RPM's. Custom grinds from Lloyd Elliott or Advanced Induction (and either of their heads) are highly regarded for the LT1
2. you can install larger valves, machine work required, in LT1/4 heads. I have 2.02/1.60....but go with whatever LE or AI suggest for their package
3. save your $ and don't buy the Edelbrock intake. Stock LT1 or 4 are better BUT you need LT4 heads to run a LT4 intake manifold
4. LT1 can EASILY be modified to exceed stock LT4...
5. Tri-Y from Dan are very good headers. with that said you may have multiple options given the intended car. Pacesetter long tubes for F body for example
6. I would consider either the stock 48 mm TB or have a stock one bored to 52 WAY before any aftermarket 58mm, especially if 350 HP is your goal.
7. you can have 350 hp to the wheels with a good head/cam package running a very small cam out of a 350 CI. I had 350/351 when mine was still 350 cu in on a baby smog legal cam
My comments
1. if you want a low RPM TQ monster, don't get the LT4 "hot" cam. It really makes its power in the upper RPM's. Custom grinds from Lloyd Elliott or Advanced Induction (and either of their heads) are highly regarded for the LT1
2. you can install larger valves, machine work required, in LT1/4 heads. I have 2.02/1.60....but go with whatever LE or AI suggest for their package
3. save your $ and don't buy the Edelbrock intake. Stock LT1 or 4 are better BUT you need LT4 heads to run a LT4 intake manifold
4. LT1 can EASILY be modified to exceed stock LT4...
5. Tri-Y from Dan are very good headers. with that said you may have multiple options given the intended car. Pacesetter long tubes for F body for example
6. I would consider either the stock 48 mm TB or have a stock one bored to 52 WAY before any aftermarket 58mm, especially if 350 HP is your goal.
7. you can have 350 hp to the wheels with a good head/cam package running a very small cam out of a 350 CI. I had 350/351 when mine was still 350 cu in on a baby smog legal cam
09-17-2013, 06:05 PM
#3
LT1 is hands down the better choice here.
To get 2.02/1.6 valves in LT1 aluminum heads you need new seats which is pissing money in the wind.
Edelbrock offerings for the LT1 are not worthwhile.
MSD ignition is at best a waste of money and if any result atall it will be to degrade the reliability of the stock system.
Clear Image's Tri-Ys are much talked about but don't buy into the hype, they are fine nothing more and in no way shape or form with the coin he charges. I have done business with him and so have friends and I would recommend you just find a SBC header that fits your chassis rather than worrying about the grossly over hyped Clear Image stuff.
With such a modest goal I would not even begin looking at a valve size change, stock valves are pretty good and will serve you just fine.
Some bowl work and a cam fitting your rpm range requirements and you should have no problem atall with that goal for cheap.
I would echo the comments about a stock TB opened up to 52mm or even one vendor I have seen offer 54mm if you really want big as possible and hassle free.
The LT4 manifold is NOT AN UPGRADE over the LT1 intake it just has more metal above the port, the internal ports are actually the same as the SMALL LT1 trapezoidal ports, the early LT1 rectangle ports are actually larger.
If done well torque is no issue in an LT1, worrying about making maximum lowend for a 2000lbs car is at best wildly ignorant, remember this engine came in the b-bodies with a base curb weight of TWICE what you say your car weighs. and a best ratio of 3.08 with most cars being 2.93 and the 4500lbs wagons often got 2.56 with a best of 2.93 with the 5000lbs tow package.
I know I just said you were wrong about a LOT but stop and think about the fact I have a over 4000lbs street car that can pull 1.5 short times and is still making good HP at the 7000 rpm pcm limits, peak HP being around 6400rpm so it is a high rpm motor AND makes more torque than your car could ever begin to use.
FWIW I have the Advancecd Induction 200cc package with a 228degree intake duration cam. Times in my sig are NA 150miles from home, valves in these heads are only 2.00/1.56 and this head has gone 9s NA in a bracket race 3400lbs f-body with a solid roller 383 putting down over 500rwhp. Does that make your questions about bigger valves seem kind of silly?
You are trying to spend a lot of money for a very modest goal.
If I were you and were making the shortblock rpm reliable I would sooner look at making broad power all the way to the pcm's limits than worrying about lownend. Unless the cam is almost deliberately screwedup an NA LT1 held below 7000rpm should have more lowend than you can use.
To get 2.02/1.6 valves in LT1 aluminum heads you need new seats which is pissing money in the wind.
Edelbrock offerings for the LT1 are not worthwhile.
MSD ignition is at best a waste of money and if any result atall it will be to degrade the reliability of the stock system.
Clear Image's Tri-Ys are much talked about but don't buy into the hype, they are fine nothing more and in no way shape or form with the coin he charges. I have done business with him and so have friends and I would recommend you just find a SBC header that fits your chassis rather than worrying about the grossly over hyped Clear Image stuff.
With such a modest goal I would not even begin looking at a valve size change, stock valves are pretty good and will serve you just fine.
Some bowl work and a cam fitting your rpm range requirements and you should have no problem atall with that goal for cheap.
I would echo the comments about a stock TB opened up to 52mm or even one vendor I have seen offer 54mm if you really want big as possible and hassle free.
The LT4 manifold is NOT AN UPGRADE over the LT1 intake it just has more metal above the port, the internal ports are actually the same as the SMALL LT1 trapezoidal ports, the early LT1 rectangle ports are actually larger.
If done well torque is no issue in an LT1, worrying about making maximum lowend for a 2000lbs car is at best wildly ignorant, remember this engine came in the b-bodies with a base curb weight of TWICE what you say your car weighs. and a best ratio of 3.08 with most cars being 2.93 and the 4500lbs wagons often got 2.56 with a best of 2.93 with the 5000lbs tow package.
I know I just said you were wrong about a LOT but stop and think about the fact I have a over 4000lbs street car that can pull 1.5 short times and is still making good HP at the 7000 rpm pcm limits, peak HP being around 6400rpm so it is a high rpm motor AND makes more torque than your car could ever begin to use.
FWIW I have the Advancecd Induction 200cc package with a 228degree intake duration cam. Times in my sig are NA 150miles from home, valves in these heads are only 2.00/1.56 and this head has gone 9s NA in a bracket race 3400lbs f-body with a solid roller 383 putting down over 500rwhp. Does that make your questions about bigger valves seem kind of silly?
You are trying to spend a lot of money for a very modest goal.
If I were you and were making the shortblock rpm reliable I would sooner look at making broad power all the way to the pcm's limits than worrying about lownend. Unless the cam is almost deliberately screwedup an NA LT1 held below 7000rpm should have more lowend than you can use.
09-18-2013, 05:47 AM
#4
Ill just elaborate on the above, which I agree 100% to, the reason not to use a 58mm throttle body when it's not needed is they can make tuning a bitch. Edelbrock offerings, especially the intake manifold, are overpriced low performance. The intake actually LOSES 4rwhp over stock LT1. Advancedinduction.com and leportworks.com are AI and LE, but there are many more out there. With just milling the stock lt1 heads 0.010 and a 0.026 head gasket to give 11.3:1 compression (lt1s can do up to 13:1 on pump gas) and AI 226/232 cam someone made 372 rwhp, that's stock valves and unported heads. You also didnt mention anything about a tune, which you MUST get, either mail order or dyno, NOT HYPERTECH, if you do any cam or change injector size. You dont need to change injectors by the way, stocks are fine to 380ish rwhp. You should hit the "pause" button and do a bit more reading before you open your wallet.
Last edited by bufmatmuslepants; 09-18-2013 at 05:59 AM.
09-18-2013, 04:10 PM
#5
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Thread Starter
Thank you for your input. This is my research pause. Im not going to open my wallet until I have hashed out some details.
I will stick with an LT1, stock intake, stock throttle body, stock valves. Just port and polish everything throughout. I will need to find a cam that will help provide a nice smooth power curve, hopefully giving me as much torque as possible throughout my chosen RPM range, say 1500-5500.
I am not looking to spend a lot of money on aftermarket parts, I would rather just blueprint/balance/port/polish what is already there (which still is not cheap). The MSD ignition is a must from what I have read. And, I hate dropping unnecessary money on headers, but I do like the concept of Tri-Y's, and the Clear Image headers seem to be the only Tri-Y headers for the LT1.
If normal SBC headers will fit, or can easily be made to fit, then I will gladly go with a different company, but I would like them to be Tri-Y design if at all possible. The headers are going to be leading to sidepipes, because I think a Z-car with sidepipes and V8 muscle would just be beautiful.
Musclepants, thank you for the exact numbers on shaving the heads and head gasket thickness. I was thinking about shaving the heads to up the compression a bit, and you provided me with real numbers. Thanks again.
96Caprice, I am trying to get as much torque evenly throughout the entire RPM range as possible. I want a broad, smooth power curve... hopefully translating into a very smooth operating vehicle.
I will stick with an LT1, stock intake, stock throttle body, stock valves. Just port and polish everything throughout. I will need to find a cam that will help provide a nice smooth power curve, hopefully giving me as much torque as possible throughout my chosen RPM range, say 1500-5500.
I am not looking to spend a lot of money on aftermarket parts, I would rather just blueprint/balance/port/polish what is already there (which still is not cheap). The MSD ignition is a must from what I have read. And, I hate dropping unnecessary money on headers, but I do like the concept of Tri-Y's, and the Clear Image headers seem to be the only Tri-Y headers for the LT1.
If normal SBC headers will fit, or can easily be made to fit, then I will gladly go with a different company, but I would like them to be Tri-Y design if at all possible. The headers are going to be leading to sidepipes, because I think a Z-car with sidepipes and V8 muscle would just be beautiful.
Musclepants, thank you for the exact numbers on shaving the heads and head gasket thickness. I was thinking about shaving the heads to up the compression a bit, and you provided me with real numbers. Thanks again.
96Caprice, I am trying to get as much torque evenly throughout the entire RPM range as possible. I want a broad, smooth power curve... hopefully translating into a very smooth operating vehicle.
09-18-2013, 05:00 PM
#6
I am telling you the fixation on torque is a mistake. Even a halfassed build with shorty headers and a higher rpm limit will have more torque than you know what to do with.
The LT1 accepts regular SBC headers. If someone makes a SBC header for your chassis or there is a commonly used alternative in that chassis with a SBC then just use that 1 5/8" longtubes would be just fine.
IMO headers are grossly overbanchraced on mild street hydraulic builds. I say this haveing tried three sets all of them originally sold by Clear Image. Save yourelf a medioum sized fortune and just buy a decent SBC header instead of the Clear Image.
The stock cams make power to 5500rpm, do yourself a favor and consider something that peaks say 61-6200 or so and will rev happily to 65-6600. You should still have a mountain of torque for such a small car but will make a fair bit more hp easily.
There was a time when I was all worried about torque too and I actually have a heavy car, normal "race weight" is in the 4200lbs neighborhood. Once I actually started modding the car I found that with the pcm 7000rpm limits a well thought out 350 should always have decent lowend. Now if you wanted an 8000rpm motor then yeah you would likely compromise lowend meaningfully.
Now granted I run more gear than you are looking at BUT the tire height, OD and lockup combined to keep the cruise rpm to likely lower than you will see and cruise torque is fine again with a cam that peaks at 6400rpm.
The LT1 accepts regular SBC headers. If someone makes a SBC header for your chassis or there is a commonly used alternative in that chassis with a SBC then just use that 1 5/8" longtubes would be just fine.
IMO headers are grossly overbanchraced on mild street hydraulic builds. I say this haveing tried three sets all of them originally sold by Clear Image. Save yourelf a medioum sized fortune and just buy a decent SBC header instead of the Clear Image.
The stock cams make power to 5500rpm, do yourself a favor and consider something that peaks say 61-6200 or so and will rev happily to 65-6600. You should still have a mountain of torque for such a small car but will make a fair bit more hp easily.
There was a time when I was all worried about torque too and I actually have a heavy car, normal "race weight" is in the 4200lbs neighborhood. Once I actually started modding the car I found that with the pcm 7000rpm limits a well thought out 350 should always have decent lowend. Now if you wanted an 8000rpm motor then yeah you would likely compromise lowend meaningfully.
Now granted I run more gear than you are looking at BUT the tire height, OD and lockup combined to keep the cruise rpm to likely lower than you will see and cruise torque is fine again with a cam that peaks at 6400rpm.
09-18-2013, 07:46 PM
#7
TECH Addict
Thread Starter
If it is not reaily apparent, this will be my first engine build, and first engine swap. That is why I am trying to stay relatively mild/reasonable (is 350rwhp reasonable?). It is also why I want to see what sort of improvements I can get with just milling/polishing the stock components (all machine work will be done by professionals, not myself).
I am focused on consistancy, more than power or torque. I want the engine to be smooth and effiencent. I figure that the LT1 will make plenty enough power when the pedal is on the floor, most engines do when the chassis they are mounted in weighs 2,000 pounds. But I will hardly ever get the opportunity to go all out, so I want a good percentage of my power/torque available early. Lower RPM range. Normal person driving conditions.
I was reading about head/valve milling to aid in efficiency in the .25"-.33" valve lift range. And also read about the Tri-Y headers helping the torque curve around the 2,500rpm range. The earlier my power curve reaches its plateau, the smoother it will be for longer. If that makes any sense. A smooth power curve all the way across the operating RPM range should equate to silky smooth vehicle operation. Unless I am just totally wrong (again).
I am planning on a 2,500-ish RPM stall torque converter. And I am not going any steeper than 3.50 rear gears to hopefully end up with a car that drives like a dream. I want it pleasant and fun, but predictable/consistant.
Thank you all for the help so far. And I apologize for any redundancy.
I am focused on consistancy, more than power or torque. I want the engine to be smooth and effiencent. I figure that the LT1 will make plenty enough power when the pedal is on the floor, most engines do when the chassis they are mounted in weighs 2,000 pounds. But I will hardly ever get the opportunity to go all out, so I want a good percentage of my power/torque available early. Lower RPM range. Normal person driving conditions.
I was reading about head/valve milling to aid in efficiency in the .25"-.33" valve lift range. And also read about the Tri-Y headers helping the torque curve around the 2,500rpm range. The earlier my power curve reaches its plateau, the smoother it will be for longer. If that makes any sense. A smooth power curve all the way across the operating RPM range should equate to silky smooth vehicle operation. Unless I am just totally wrong (again).
I am planning on a 2,500-ish RPM stall torque converter. And I am not going any steeper than 3.50 rear gears to hopefully end up with a car that drives like a dream. I want it pleasant and fun, but predictable/consistant.
Thank you all for the help so far. And I apologize for any redundancy.
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09-18-2013, 08:20 PM
#8
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OP: What do you plan on using for:
Transmission
Rear axle
Rear Suspension
Tire type/size
I have friends with 280Z's and am familiar with the earlier 240 and 260. Traction is going to be your biggest challenge unless you plan on doing major surgery to the rear to fit large tires.
-Dave
Transmission
Rear axle
Rear Suspension
Tire type/size
I have friends with 280Z's and am familiar with the earlier 240 and 260. Traction is going to be your biggest challenge unless you plan on doing major surgery to the rear to fit large tires.
-Dave
09-18-2013, 08:28 PM
#9
2500 stall and 3.50 gears are fine and you don't need to build for torque to be happy with them.
You are much too worried about lowend, only way you will have a lowend problem is if you screw this up badly. One briefly popular custom cam guy around here used to be able to deliver no lowend but even his junk would have given you more torque than you can handle.
You are much too worried about lowend, only way you will have a lowend problem is if you screw this up badly. One briefly popular custom cam guy around here used to be able to deliver no lowend but even his junk would have given you more torque than you can handle.
09-19-2013, 05:35 AM
#10
You keep saying "blueprint, milling, polishing" but in reality you can either use a stock bottom end from Craigslist or just get one refreshed with new cam rod and main bearings, rods resized for ARP bolts, not have it rebalanced, reuse the main bolts if its before 96 when they went torque to yield, and have someone competent put it back together, and it will withstand 7000 rpm and whatever you can throw at it NA. 350 is a modest goal, can be done with bumping compression and a decent cam, but if your refreshing the bottom end with ARP rod bolts, might as well go with ported stock heads and a cam, and shoot for 400-430rwhp. "Polishing" is old school talk, polishing a surface too much causes the air to slow down, thing a golf ball, you want the surface to be slightly rough so it holds air in little pockets because air slides over air better than air slides over metal (golf ball divots).
Whoever told you MSD is a must is probably old school sbc guy, none of that applies here, my MSD opti has been trouble free for 7 years and 40k miles but so are stock replacements. Stay with stock replacement ignition and save $$$. And don't let anyone who is a sbc/bbc guy try to convince you to stay around 10:1 to be pump gas friendly, the reverse cooling and aluminum heads let us run close to 13:1 no issue with a proper tune.
Whoever told you MSD is a must is probably old school sbc guy, none of that applies here, my MSD opti has been trouble free for 7 years and 40k miles but so are stock replacements. Stay with stock replacement ignition and save $$$. And don't let anyone who is a sbc/bbc guy try to convince you to stay around 10:1 to be pump gas friendly, the reverse cooling and aluminum heads let us run close to 13:1 no issue with a proper tune.
09-20-2013, 04:25 PM
#11
TECH Addict
Thread Starter
For no reason in particular, I have this weird 350/350/3.50 fixation. So I am staying with the 350ci displacement, mating the LT1 to a turbo 350 transmission (they make 240z swap kits for it, and I want an auto), and I am going with 3.50 rear gears to keep it relatively street friendly (my Cadi CTS has 3.42's and drives like a dream).
This car is going to be a daily driver, fun on the weekends car. Like I said, I have a Cadillac CTS (3.6L V6), for all my grocery getting/family man needs. The Caddy is my car-seat car. I am looking for something sans car-seats. Something just for fun. But I want it to be a model of perfection when it comes to the overall driving experience. I have fun when I drive (spirited driver, if you will), and I want a car that is built just for that. If someone else were to drive this car, I want them to walk away smiling, thinking that is how every car should drive. That is why I want it to have good road manners and be predictable. Nothing jumpy or jerky. Just smooth, pure fun.
And to be clear, I am not necessarily focusing on low-end torque/power. I just want a broad, smooth power curve. Hoping for as much available power as soon as possible for a nice consistent/predictable power curve with a broad plateau. I understand that this engine will have plenty of low-end available right from the start, especially when considering the chassis it will be sitting in.
I am planning on having the stock rotating assembly knife-edged/lightened, balanced, and cyro'ed. Valve job with stock valves. Mild porting of the stock heads, nothing too fancy as I am staying natural aspiration. Shaving the heads to up the compression a bit (as Musclepants said). Mainly just focusing on having everything (intake, heads, headers) port-matched. Probably open the TB up a little, once again, nothing fancy. ARP bolt kit (including heads studs and header bolts) for the entire engine, for sure, just to be safe.
Another thing I have read about and like the thought of is the valve overlap, where the exhaust valves are still open for a bit when the intake valves open up, creating suction to fully fill the combustion chamber. Still reading up on this, but I really like the sounds of it so far.
This car is going to be a daily driver, fun on the weekends car. Like I said, I have a Cadillac CTS (3.6L V6), for all my grocery getting/family man needs. The Caddy is my car-seat car. I am looking for something sans car-seats. Something just for fun. But I want it to be a model of perfection when it comes to the overall driving experience. I have fun when I drive (spirited driver, if you will), and I want a car that is built just for that. If someone else were to drive this car, I want them to walk away smiling, thinking that is how every car should drive. That is why I want it to have good road manners and be predictable. Nothing jumpy or jerky. Just smooth, pure fun.
And to be clear, I am not necessarily focusing on low-end torque/power. I just want a broad, smooth power curve. Hoping for as much available power as soon as possible for a nice consistent/predictable power curve with a broad plateau. I understand that this engine will have plenty of low-end available right from the start, especially when considering the chassis it will be sitting in.
I am planning on having the stock rotating assembly knife-edged/lightened, balanced, and cyro'ed. Valve job with stock valves. Mild porting of the stock heads, nothing too fancy as I am staying natural aspiration. Shaving the heads to up the compression a bit (as Musclepants said). Mainly just focusing on having everything (intake, heads, headers) port-matched. Probably open the TB up a little, once again, nothing fancy. ARP bolt kit (including heads studs and header bolts) for the entire engine, for sure, just to be safe.
Another thing I have read about and like the thought of is the valve overlap, where the exhaust valves are still open for a bit when the intake valves open up, creating suction to fully fill the combustion chamber. Still reading up on this, but I really like the sounds of it so far.
09-20-2013, 04:35 PM
#12
TECH Addict
Thread Starter
Oh yeah, swapping in a R200 rear-end, with the 4-pinion LSD. Not sure about tire size. Probably something along the lines of 245's front, 275's rear. Maybe roll the fenders and add widebody flares, see if I can fit 265's and 305's.
09-20-2013, 04:42 PM
#13
I am planning on having the stock rotating assembly knife-edged/lightened, balanced, and cyro'ed.
I might deck the block some instead of the heads if you will have the engine apart anyway. The stock gasket is really thick and a thin gasket is already a nice gain, milling the block can make a bigger difference than the heads too since it is a full bore diameter being shortened not just a chamber being milled down.
Far as the gearing, if you want to have similar cruise rpm to the CTS you would want to use a OD lockup tranny not the TH350 which has no OD and I don't think the lockup version is desirable for performance use.
IMO you need to actually check out some cars.
09-20-2013, 06:38 PM
#14
TECH Addict
Thread Starter
How is reducing rotating mass a joke? There are a lot of things that I do not understand, clearly, but I have always thought less moving mass at any one time is a good thing. Knife-edging the crank reduces its mass, and reduces the amount of oil drag (not that oil, a lubricant, has that much drag).
I am no expert, but all of that seems like it would be beneficial.
Thank you for the advice on decking the block, not the heads. That makes perfect sense.
I know there are TH350 swap kits available for the 240z. There are not LT1 swap kits. But an LT1 can be mated to a TH350. Mounting the transmission first will locate the engine and make fabricating engine mounts much easier.
To be honest, I do not want a computer controlled transmission. If I had the money, I would carb the LT1 and ditch all the computers completely. I just REALLY like the reverse cooling system for some reason, otherwise I would just go the easy route and swap in a 350 Vortec.
All that being said, I am not totally opposed to using the 4L60 that is mated to a lot of LT1's. That way I could use the stock ECM/PCM, and just have them tuned.
I am no expert, but all of that seems like it would be beneficial.
Thank you for the advice on decking the block, not the heads. That makes perfect sense.
I know there are TH350 swap kits available for the 240z. There are not LT1 swap kits. But an LT1 can be mated to a TH350. Mounting the transmission first will locate the engine and make fabricating engine mounts much easier.
To be honest, I do not want a computer controlled transmission. If I had the money, I would carb the LT1 and ditch all the computers completely. I just REALLY like the reverse cooling system for some reason, otherwise I would just go the easy route and swap in a 350 Vortec.
All that being said, I am not totally opposed to using the 4L60 that is mated to a lot of LT1's. That way I could use the stock ECM/PCM, and just have them tuned.
Last edited by DavidBoren; 09-20-2013 at 06:48 PM.
09-20-2013, 07:39 PM
#15
Ok a lot I want to say but I'll try anyways. First off I have a 93 vette and am on my second lt4 build (370ci lt4 solid roller) built for 8-8500 rpms. In short I don't care for torque. Well I do, it's just a 370/383/396 already has enough so I built my motor for maximum hp up top. If you are at 2800 lbs, I suggest you don't care for torque as well lol 
it's just going to destroy tires.
First I want to say as much as I love the ltx for your project I would say go lsx. It's lighter and for a light car it can make a difference. For a 350rwhp goal.. Put headers on a junkyard ls1 and you're pretty close already. Not to get Into a ls1/lt1 peeing match here, but a stock ls1 is just a newer platform that is improved in almost every way. In my opinion may as well start there.
On to knife edging and stuff.. Yes that stuff will make people here roll their eyes and lAugh hysterically. My original crank from my 93 sat on the side of the road for 3 weeks before someone picked it up. A few days later someone put it back. Think that tells you what it's worth. For the price of all that machine work you can pick up a fine lightweight forged crank. Now were talking.
Check out elllewein racing engines. Yes he's my builder but I love that he documents his builds. Take a look at some of his builds and you can familiarize yourself with what parts people use and why and what the goals are.
Some people on here may upset you with their replies but take any attitude with a grain of salt. There is a LOT of knowledge and experience with ltx in this section/ls1tech.
it's just going to destroy tires.First I want to say as much as I love the ltx for your project I would say go lsx. It's lighter and for a light car it can make a difference. For a 350rwhp goal.. Put headers on a junkyard ls1 and you're pretty close already. Not to get Into a ls1/lt1 peeing match here, but a stock ls1 is just a newer platform that is improved in almost every way. In my opinion may as well start there.
On to knife edging and stuff.. Yes that stuff will make people here roll their eyes and lAugh hysterically. My original crank from my 93 sat on the side of the road for 3 weeks before someone picked it up. A few days later someone put it back. Think that tells you what it's worth. For the price of all that machine work you can pick up a fine lightweight forged crank. Now were talking.
Check out elllewein racing engines. Yes he's my builder but I love that he documents his builds. Take a look at some of his builds and you can familiarize yourself with what parts people use and why and what the goals are.
Some people on here may upset you with their replies but take any attitude with a grain of salt. There is a LOT of knowledge and experience with ltx in this section/ls1tech.
09-20-2013, 08:51 PM
#16
Reducing mass and knife edging have their place, a stock crank in a 350rwhp isn't that place.
Far as the above poster saying consider LS. I have told a LOT of guys that if retrofitting an injected V8 into a car that didn't come with one I would do a 5.3l before an LT1. You can even find those with aluminum blocks.
Far as the above poster saying consider LS. I have told a LOT of guys that if retrofitting an injected V8 into a car that didn't come with one I would do a 5.3l before an LT1. You can even find those with aluminum blocks.
09-20-2013, 09:28 PM
#17
TECH Addict
Thread Starter
Nastyc4, thank you for your reply. I will look into an LS1. I did not realize they were cheap as they are. And I did not realize they will pretty much bolt right up to a TH350 transmission. Which makes the swap pretty easy. The reason I am so set on the turbo 350 transmission, is because there are kits to mount it that even include the driveshaft. And a TH350 can be picked up for cheaps.
The LS1 weighs the same as the all iron I-6 thats in the car right now, which is pretty amazing all things considered. Plus, down the road, I could put a 3.9" stroker crank in it, making a totally square 372ci LS1. And that makes me smile.
I, obviously, still have a lot to consider and a lot of research to do. Thank you all for the advice and the replies.
The LS1 weighs the same as the all iron I-6 thats in the car right now, which is pretty amazing all things considered. Plus, down the road, I could put a 3.9" stroker crank in it, making a totally square 372ci LS1. And that makes me smile.
I, obviously, still have a lot to consider and a lot of research to do. Thank you all for the advice and the replies.
09-27-2013, 06:30 AM
#18
TECH Resident
Lots of good advice above and I'll throw my 0.02 in as well.
I don't think you need to go near any kind of ported LT1 head machining work for the power levels you are looking for.....I think a simple cam and roller rocker swap will get you that.
My stock head, stock rotating assembly, and stock displacement LT1 with a CC503 cam, 1.6rr, longtube headers, and around 0.005" decked off the heads is pushing over 400hp at the crank. I have not dyno'd the car, but my friend's C6 vette with an LS2 is running 84mph at the end of the 1/8mile while I'm 87mph at the traps. That LS2 is pushing 400 at the crank so with my traps being higher, I've got just a little more than him. My car has run a best of 8.3@89mph in the 1/8th and that is with a very crappy 60' and crappy street tires.
That being said, my plans are to purchase either LE2 or AI heads myself. If you are purchasing heads separate from the short block or want to upgrade them, those are two of the best sources to look at.
The LT4 was a good factory package, but I feel that with what LE and AI has done with stock LT1 heads there is really no need to go near LT4 intake/heads.
Given the LS1 options today, it would be hard to consider the LT1 unless you are getting a really good deal on it. Don't get me wrong, I really like my LT1, but the LS stuff with the tuning software offered in HPtuners or EFI Live is very nice.
I don't think you need to go near any kind of ported LT1 head machining work for the power levels you are looking for.....I think a simple cam and roller rocker swap will get you that.
My stock head, stock rotating assembly, and stock displacement LT1 with a CC503 cam, 1.6rr, longtube headers, and around 0.005" decked off the heads is pushing over 400hp at the crank. I have not dyno'd the car, but my friend's C6 vette with an LS2 is running 84mph at the end of the 1/8mile while I'm 87mph at the traps. That LS2 is pushing 400 at the crank so with my traps being higher, I've got just a little more than him. My car has run a best of 8.3@89mph in the 1/8th and that is with a very crappy 60' and crappy street tires.
That being said, my plans are to purchase either LE2 or AI heads myself. If you are purchasing heads separate from the short block or want to upgrade them, those are two of the best sources to look at.
The LT4 was a good factory package, but I feel that with what LE and AI has done with stock LT1 heads there is really no need to go near LT4 intake/heads.
Given the LS1 options today, it would be hard to consider the LT1 unless you are getting a really good deal on it. Don't get me wrong, I really like my LT1, but the LS stuff with the tuning software offered in HPtuners or EFI Live is very nice.
Last edited by ACE1252; 09-27-2013 at 06:49 AM.
09-27-2013, 07:53 AM
#19
I think this guy just likes to hear himself "talk car".
1st off, NO ONE "polish's" a cylinder head anymore, when people use this terminology it shows how much you DON'T know. That crap went out the window decades ago.
To fix ALL your issues, call Advanced Induction.
For reference, years ago I built a 355 LT1 for my 94 Z28.
Stock 2 bolt block
Stock crank
Stock old style rods with ARP bolts
Balanced it
.030 Probe pistons 10.9 compression
Block was zero and square decked
LT1 heads ported by Killians Porting Service
Stock intake owner ported
52MM throttle body
Crower cam 220/224@.050
Roller rockers
All the bolt ons
Mail order tune.
9 inch with a 4.11 gear
The car was never dynoed, on Nitto drag radials it ran 90 mph in the 1/8 mile in a 3750 lb Fbody. So it had to be bumping 380-390 to the wheels through the 9 inch.
Lots of torque, was a ball to drive.
To the OP, if you want to make 350 to the wheels, all you need is a stock bottom end, bolt ons and a cam.
/thread
1st off, NO ONE "polish's" a cylinder head anymore, when people use this terminology it shows how much you DON'T know. That crap went out the window decades ago.
To fix ALL your issues, call Advanced Induction.
For reference, years ago I built a 355 LT1 for my 94 Z28.
Stock 2 bolt block
Stock crank
Stock old style rods with ARP bolts
Balanced it
.030 Probe pistons 10.9 compression
Block was zero and square decked
LT1 heads ported by Killians Porting Service
Stock intake owner ported
52MM throttle body
Crower cam 220/224@.050
Roller rockers
All the bolt ons
Mail order tune.
9 inch with a 4.11 gear
The car was never dynoed, on Nitto drag radials it ran 90 mph in the 1/8 mile in a 3750 lb Fbody. So it had to be bumping 380-390 to the wheels through the 9 inch.
Lots of torque, was a ball to drive.
To the OP, if you want to make 350 to the wheels, all you need is a stock bottom end, bolt ons and a cam.
/thread
Last edited by FASTFATBOY; 09-27-2013 at 08:00 AM.
09-27-2013, 09:17 AM
#20
Village Troll 
iTrader: (2)
This is not going to be a high-revving engine, so I want as much torque available as quickly as possible. And I want a nice smooth power curve for nice street manners. I want the car to drive smooth, I dont need anything fancy... its a 5.7L V8 going into a 2,000 pound car.