347 forged bottom end Pros & Cons
I just want to have a good bottom end to handle a 200 shot max. If i ever wanted to go that big Im thinking I will just shoot a 150 until I start getting beat. As long as I am mid 11's N/A & mid to lo tens on the button I will be happy. Can I go mid to lo 10's with a 347 bottom end and a Heads and cam package? (I'm thinking a head and cam package from TSP) MS3 or 4.
Here's something for ya. We dropped a completely stock LQ9 into my old car, threw an LS6 intake, longtubes and an MS4 in it and went 10.7 on a 100 shot--with a **** tune at that. That's in a full weight car on drag radials too.
It can be done with either combo.
The price is to open to different facts. You can find somebody to build you a 347 for the low local. or you can just order one and have all the parts there and done. Im not a fan of a 383 I think in the ls world they are pointless. Hell you have a 4.00 crank might as well throw it in a ls2 or lq9 with the right rods and be done with it. Either way you look at it. 408 on spray is killer 347 on spray is a killer, But on the 408 you might not have to spray as much to wax some ***. The 347 built right will put u in the area of 480 hp to the wheels maybe more or less na, a built 408 will put you closer to 500+ na. IMHO the car will be alot funner to drive with the 408 because of the tq increase and hp. Streetable in my book is like this, Type of gas is mostly used Ie 93 pump or mix of c16, With a good tune big cams can be tame, and gears for the auto guys 3.73 or 4.10 gas milage is a big factor because the motor is spun higher at 60 on the high way. My car is pump gas six speed and I drive it like its stock everyday. 18 city 26 high way.
I just want to have a good bottom end to handle a 200 shot max. If i ever wanted to go that big Im thinking I will just shoot a 150 until I start getting beat. As long as I am mid 11's N/A & mid to lo tens on the button I will be happy. Can I go mid to lo 10's with a 347 bottom end and a Heads and cam package? (I'm thinking a head and cam package from TSP) MS3 or 4.
TSP did 9.82 on a stock bottom end but the car is a feather weight.
To run those times at a more "street friendly" weight will be tough to near impossible with a N/A 347 and will take a good shot of gas. If you dont mind driving a whored out drag car on the street than you may be fine though.
Everyone knows the pros.
You can make more power with the supporting mods safely.
Not so much worry about rod bolts. Am i going to break xxxxx today?
If you are going to do a forged 346 and not make more than lets say 800rwhp i would do some nice pistons, nice rods, and keep the stock crank. budget motor? Talk to TSP.
But if you spend like 500$ more you can get a 408.
You can make more power with the supporting mods safely.
Not so much worry about rod bolts. Am i going to break xxxxx today?
If you are going to do a forged 346 and not make more than lets say 800rwhp i would do some nice pistons, nice rods, and keep the stock crank. budget motor? Talk to TSP.
But if you spend like 500$ more you can get a 408.
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Yes you can but at that point it will be more about weight and setup than actual HP. A 12 bolt with 3:73's or 4:10's, full suspension, MT radials, QA1 shocks, and a lot of weight reduction will get you those times.
TSP did 9.82 on a stock bottom end but the car is a feather weight.
To run those times at a more "street friendly" weight will be tough to near impossible with a N/A 347 and will take a good shot of gas. If you dont mind driving a whored out drag car on the street than you may be fine though.
TSP did 9.82 on a stock bottom end but the car is a feather weight.
To run those times at a more "street friendly" weight will be tough to near impossible with a N/A 347 and will take a good shot of gas. If you dont mind driving a whored out drag car on the street than you may be fine though.
Mid 11s N/A and Mid 10s on Nitros is no problem with a SB/Heads/Cam package.I have no weight reduction. My cars interior is like it came from the factory and still has the 10 bolt rearend. Not to mention I weigh over 300#s. I have no trouble running 11's N/A and I'm sure if I were to let the crew at RPM put a 200 shot of nitros on her she would have no trouble hitting the 10s. I bought the TSP 347 because I went thru 3 stock 347s in 2 years. If it wasn't a rod bearing it was something else. This TSP SB/2.5 heads/MS4 has held together for over a year and a half now. So I can say I bought my TSP 347 SB for peace of mind. It is daily driven with the AC running and hits the Test and Tune at the local track on the weekends. The only problem I've had with Jon at TSP is the T-shirts need a pocket mod so I got somewhere to hang my reading glasses.
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You will get lots of opinions on 408 vs. 347 but I believe you might be missing the most critical piece for making good hp/tq numbers - your heads.
I would bet a 347 with good heads can give a 408 with crappy ones a good run. What do you have on top now and what do you plan to use in the future.
I would bet a 347 with good heads can give a 408 with crappy ones a good run. What do you have on top now and what do you plan to use in the future.
You will get lots of opinions on 408 vs. 347 but I believe you might be missing the most critical piece for making good hp/tq numbers - your heads.
I would bet a 347 with good heads can give a 408 with crappy ones a good run. What do you have on top now and what do you plan to use in the future.
I would bet a 347 with good heads can give a 408 with crappy ones a good run. What do you have on top now and what do you plan to use in the future.
My 347 has been good to me and running strong for 3 years now, but a couple months after it was up and running I regretted my choice. I was trying to get my car up and running as cheaply as possible so I went the 347 route. Had I saved another month or so I could have gone the stroker route.
IMO it is not worth it to buy the parts and have a local machine shop machine, balance, and properly assemble(most people do not have the tools to measure clearances) your current engine. To do it right you will spend as much or more than you would to buy one pre-assembled from one of the site sponsors. Then as mentioned you still have your stock motor to do with as you please, whether you sell it or keep it as a back up is up to you. As far as the head/cam debate goes he has to buy them anyway so the cost difference is minimal at this point. Had the OP already had a set of heads and a cam more suited to a 346/347 it would be an issue.
Sure a 347 may get you the results you want now, but a couple years(or months) down the road you will be kicking yourself and saying "for 5-600 more I could have gone with a 408". Also if you do decide to go with a new shortblock the iron block 370 is normally a tad cheaper than a 347. More cubes for less money is kind of a no brainer. I was hung up on the weight issue as well, but after putting a bone stock LQ9 in a TA for friend I can tell you that the weight is a non issue.
IMO it is not worth it to buy the parts and have a local machine shop machine, balance, and properly assemble(most people do not have the tools to measure clearances) your current engine. To do it right you will spend as much or more than you would to buy one pre-assembled from one of the site sponsors. Then as mentioned you still have your stock motor to do with as you please, whether you sell it or keep it as a back up is up to you. As far as the head/cam debate goes he has to buy them anyway so the cost difference is minimal at this point. Had the OP already had a set of heads and a cam more suited to a 346/347 it would be an issue.
Sure a 347 may get you the results you want now, but a couple years(or months) down the road you will be kicking yourself and saying "for 5-600 more I could have gone with a 408". Also if you do decide to go with a new shortblock the iron block 370 is normally a tad cheaper than a 347. More cubes for less money is kind of a no brainer. I was hung up on the weight issue as well, but after putting a bone stock LQ9 in a TA for friend I can tell you that the weight is a non issue.
