I'm getting ready to yank the motor and forge it out before I end up throwing chunks of pistons into the heads. I'm trying to decide if I want to go with a 370 or a 408 and what compression I am going to put it at. I'm thinking between 9.5 and 10:1 on compression. I will be using the AFR 225cc heads I have now and probably a different cam than the GT2-3 that is in there now.

I am going to leave the turbo on there with 3.5 dp and 4" exhaust. Any suggestions and experiences would be appreciated.

 

I would go with the 370 becouse I have been reading the deck heigth on a LS is not suitable for a 408 if you want it to last a long time. The piston apparently partially comes out of the bottom of the block which kills the bore sealing thus effects life span. This was in a issue of car craft if you wanna look it up.

As for static compression ratio it depends on total boost you wanna run, but I would probily go with 9-1cr so I can run double digit boost easy.

 

I'd go with the 370 and just turn the boost up.

Backpressure seems to be a big issue with big cubic inch engines and smaller(relative) sized single setups. Put a T88 sized turbo on the 370 and let it eat!!

 

John

 

YAAA.... +1 to that.

 

I love the torque that my 408 has. I would have been happy if I just forged my 6.0 with the heads, cam, and intake. I would like to have back the mpg that I lost.

 

I am just goin to be building a forged 370 this year. Nice thing is it will be cheaper to build than a 408. You can use the stock crank from a 6L which from what I heard and read up on the stock cranks are good to 1000hp which I wont be coming close to that. And price for machine work would be more on a 408. I figured a forged 370 with some stock l92 heads,intake and custom cam should put down some decent power for what I am wanting to do. Thats the plan for right now anyways lol

 

370 and wick that ****** up! Less Cubes, more boost! DOIT

 

Its going to be mostly street duty, and gas mileage isnt really anything im concerned with on it, cause it only gets 12 now. Thats why I bought the pos rice burner for daily use. I really dont see myself going over 600- 700 rwhp with it, and want driveability. But it would be nice to be able to turn up the wick and get retarded with it.

 

408 12 psi...9.59 @ 12psi.....4000# 10.3/4 cr