Ported heads and bigger cam or don't bother?
 

I am finishing a forged 347 with -25cc pistons,stock ls6 heads w/dual springs,ls6 cam, ls6 intake,and 76mm turbo. Should I pop for ported heads and bigger cam or just run what I have? I know people have had good luck with this combo but I couldn't find power #'s. Just wondering how much I am leaving on the table?

Wow, -25cc pistons in a 347??!?!! That is a static compression level of 8.1:1, way too low IMO. I would put a set 5.3L heads, 58cc chambers, on to get the compression level up to 8.7:1. The LS6 cam is more S/C friendly with the longer duration and lift on the exhaust side. If the block is not in the car yet, I would think about swapping out the cam for a more turbo friendly cam( one that has more duration and lift on the intake side ).

Keith

Less powerful engine = more boost to hit a given number.

I think you should leave it, you have a low compression 325rwhp motor, so you can boost it hard to get good numbers. You can always change stuff later. I'd love to hear how you dyno and what trap speeds you run.

My motor is 8:1.

i think you should leave it also.......i have seen some people on here gain some pretty good numbers with a ls6 cam over stock. you will probally spend a min. of 2k on heads and cam. make the turbo work. i would like the numbers off this setup too.

I am getting a 408 built right now for a turbo and it will be 8:1 CR, like above said you will be able to throw a shit load of boost at it, and pump gas too.

Here is the link to Wiseco
http://www.flatlanderracing.com/wise...ons-sbc07.html

On there they say with 62cc heads a compression ratio of 8.6 to 1. Is this correct? I was shooting for 8.5 to 1

Sounds like right around there. I am running ~72cc heads.

What dish are you running?