A different LT1 build-up.
Thread Starter
Teching In
Joined: Aug 2004
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A different LT1 build-up. I have a slightly different power combination I'm looking for from my LT1. Instead of just looking for insane horsepower, I have different goals. I want to get about 400 horses, which I know isn't difficult. But, I want 500-550+ torque, and I'm looking to get it at a very low rpm. Think sub 3000 rpms, and keeping that torque for as long as possible. The reason for this, is my car. I own a 96 Fleetwood, so 4400 lbs of car to get moving off the line. Plus, this is my daily driver, so I'd like the power to be reliable, and not blow my mother up doing this. I also want to avoid having a huge lumpy idle, or that loud muscle car rumble. It's a Cadillac 
, and a sleeper, can't give away too much now. 
I also am currently on the stock 2.56 gear. But, I am leaning towards a 3.42 from the towing package option on the Fleetwoods, or a 3.23 if I can get the programming easily. As I said, daily driver, can't go too extreme.
I figure I'll probably have to use a supercharger or turbocharger of some sort to do this.
, and a sleeper, can't give away too much now. I also am currently on the stock 2.56 gear. But, I am leaning towards a 3.42 from the towing package option on the Fleetwoods, or a 3.23 if I can get the programming easily. As I said, daily driver, can't go too extreme.I figure I'll probably have to use a supercharger or turbocharger of some sort to do this.
TECH Apprentice
Joined: Aug 2004
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Pretty unrealistic to design a setup for 400 peak HP but 500+ TQ from under 3K on. Remember HP is a function of torque....if you're wanting some good torque down low you have a couple of options.....
Swap in a diesel or turbo a stroker. The longer stroke will give more torque and turbo's are famous for great torque peaks as opposed to S/C where it is proportional to RPM. With the torque you are going to have HP.....they go hand in hand.
Swap in a diesel or turbo a stroker. The longer stroke will give more torque and turbo's are famous for great torque peaks as opposed to S/C where it is proportional to RPM. With the torque you are going to have HP.....they go hand in hand.
Launching!
Joined: Apr 2004
Posts: 271
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From: Regina, SK
Definitely a bigger displacement (383 cubes or bigger) will get you towards your torque goal. And a cam would be crucial for engineering in lots of low-down torque; maybe something with even less lift than the stock cam. Seems to me I'd heard long, narrow intake runners in the manifold gives more torque at the expense of less high rpm breathing (ie: lowers redline and decreases peak HP). I've never heard of such a thing for the LT1, but maybe some machinist could fab up a custom manifold tuned for torque.
If you want low-down pulling power, how about 3.73 gears instead?
If you want low-down pulling power, how about 3.73 gears instead?
TECH Senior Member
Joined: Jun 2003
Posts: 9,339
Likes: 3
From: NYC metro area
Definitely gotta go with a stroker. Making torque would rule out the blower, a turbo would work well. But as far as making that much more torque than power, that would be the hard part. John95z28 had some pretty good ideas regarding intake. You could do the same on the exhaust side to raise torque, but ultimately you'll just be decreasing the all-around power that the motor will make. The idea is interesting, but in my opinion pretty unpractical.
You could do a 383 stroker with a Whipple blower on it and it should get you close to what you want. You wouldn't need a lumpy cam (blowers dont like them anyway) and you would make a ton of tq. 
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Thread Starter
Teching In
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Well I'm not saying I want ONLY 400 horses. What I mean is anything over 400 horses, is more than enough. The reason for the torque focus is, as I said, the car. I dont want to go all the way to a 3.73 gear, because of driveability/mileage. I do see some highway miles, so it's honstly worth it to me to keep a slightly tall gear. The stock 2.56 is TOO tall, but a 3.23 or 3.42 would be a good midrange gear for me.
I also do want to avoid a lumpy cam. It's a Cadillac, I have to keep some smoothness, even if I am adding a bunch of power. I figured going to a 383 stroker would probably be among the best plans. I also had a feeling that forced induction would also be among the best plans. I was wondering, with the layout and size of the engine bay, would making a little twin turbo 383, running low boost be unreasonable? (When I mean low boost, 6-8 PSI) Am I getting too complex or colorful here? I figure a small twin turbo would reduce any spool/turbo lag issues, keep the screaming down, etc.
I also do want to avoid a lumpy cam. It's a Cadillac, I have to keep some smoothness, even if I am adding a bunch of power. I figured going to a 383 stroker would probably be among the best plans. I also had a feeling that forced induction would also be among the best plans. I was wondering, with the layout and size of the engine bay, would making a little twin turbo 383, running low boost be unreasonable? (When I mean low boost, 6-8 PSI) Am I getting too complex or colorful here? I figure a small twin turbo would reduce any spool/turbo lag issues, keep the screaming down, etc.
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TECH Enthusiast
Joined: Feb 2004
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From: Foley, Alabama-southern Alabama
Does the Caddy have an od tranny?If so you can go to 3.73 gears.Also a stroker is what you need,I go a 3 7\8 or 4 in if possible.You want to keep your intake ports small but get a good 3 angle valve job and pocket port your heads you only need about 255 cfm at .500 lift get your exhaust at about 190 or so.Get your cr at about 10 to 1 or so.Now on your cam get a Comp Cams custom grind with 224 intake and 230 exhaust with about 550 lift with 1.65 rollerrockers with a lda of 109 installed on 107 atdc.I have a 230-236 in a 408 with Vortec(highly ported)Also lt-1 has same intake port as Vortec. This cam idles very well as has decent vacuum too.I f you really want low end torque go with the tunedport set-up.for headers go 1 5\8 with long primaries and good exhaust( I have 3in to 2.5 Dr Gas X-pipe with xr-1 Borla stainless mufflers and it sounds great(no roar like turbo mufflers)You"ll have over 500 ft lbs at 3000 or so and about 435 to 450 hp at about 5500.
Or on a different note get an old 500 ci Caddy and mod it,that would do 500 torque at 2500 or less!!!!p.s. get the longest con. rod you can fit 6.0 at least!
Or on a different note get an old 500 ci Caddy and mod it,that would do 500 torque at 2500 or less!!!!p.s. get the longest con. rod you can fit 6.0 at least!
Originally Posted by ShadowLvr
I have a slightly different power combination I'm looking for from my LT1. Instead of just looking for insane horsepower, I have different goals. I want to get about 400 horses, which I know isn't difficult. But, I want 500-550+ torque, and I'm looking to get it at a very low rpm. Think sub 3000 rpms, and keeping that torque for as long as possible. The reason for this, is my car. I own a 96 Fleetwood, so 4400 lbs of car to get moving off the line. Plus, this is my daily driver, so I'd like the power to be reliable, and not blow my mother up doing this. I also want to avoid having a huge lumpy idle, or that loud muscle car rumble. It's a Cadillac , and a sleeper, can't give away too much now. I also am currently on the stock 2.56 gear. But, I am leaning towards a 3.42 from the towing package option on the Fleetwoods, or a 3.23 if I can get the programming easily. As I said, daily driver, can't go too extreme.
I figure I'll probably have to use a supercharger or turbocharger of some sort to do this.
, and a sleeper, can't give away too much now. I also am currently on the stock 2.56 gear. But, I am leaning towards a 3.42 from the towing package option on the Fleetwoods, or a 3.23 if I can get the programming easily. As I said, daily driver, can't go too extreme.I figure I'll probably have to use a supercharger or turbocharger of some sort to do this.
You may consider a big block too. A 502 could produce those numbers all day long without even breaking a sweat.
Good luck....
Mike
You just need a big stall(3600 or so, it'll still be very streetable) plus a decent amount of nitrous on a heads/cam 355. Put down ~385rwhp/375rwtq (with a baby cam) on motor and run a 200 shot of juice. 
A lot cheaper than a turbo setup.
A lot cheaper than a turbo setup. Thread Starter
Teching In
Joined: Aug 2004
Posts: 38
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Not going the nitrous route again. Had a direct port setup on my previous car, and it was more hassle than it was worth. I want the power to always be available, not have to refill it every 3-4 runs.
ShadowLvr, if you haven't already, check out www.impalaSSforum.com 
There are thousands of us big body folks making these boats go faster.
Anyway, I've had 3.08s, 3.73s and now 4.10s in the rear end of my 96 Impala SS. So far it's gone as quick as 13.41@101.7 in the quarter with just bolt-ons.
The 3.73s are more than reasonable with the 4L60E. I'm betting that your 'wood has 28" tires if they are the stock size which helps keep cruising RPM down while helping with the smooth ride. Your plan of going 3.42s will be a big step up from the 2.56s. I have a friend with a Roadmaster that went to 4.10s from his 2.56s and it really woke his car up!
The biggest problem with making tons of torque is getting it off the line. Unless you put some extra sticky tires on, all that torque will be wasted. That's why I'm building my car to give up a little low end while gaining top end. Of course, I also have a fairly loose converter, so traction on the street is already a problem.
There are thousands of us big body folks making these boats go faster.Anyway, I've had 3.08s, 3.73s and now 4.10s in the rear end of my 96 Impala SS. So far it's gone as quick as 13.41@101.7 in the quarter with just bolt-ons.
The 3.73s are more than reasonable with the 4L60E. I'm betting that your 'wood has 28" tires if they are the stock size which helps keep cruising RPM down while helping with the smooth ride. Your plan of going 3.42s will be a big step up from the 2.56s. I have a friend with a Roadmaster that went to 4.10s from his 2.56s and it really woke his car up!
The biggest problem with making tons of torque is getting it off the line. Unless you put some extra sticky tires on, all that torque will be wasted. That's why I'm building my car to give up a little low end while gaining top end. Of course, I also have a fairly loose converter, so traction on the street is already a problem.
