dschmittie1

iTrader: (64)

OK so I currently have a stock headed Forged 347 that is about 9.2:1 CR (-8.6cc piston) running 13# making 630rwhp. I am looking to swap out to some heads that flow a little better. I have a set of stock 317 heads sitting that I was going to have ported and use for a 370 build but I am thinking about staying with my 347.

So do I use the 317 heads but mill them down to a 70 cc head so I am around 9.0:1 CR and repulley the blower

Or

Do I pick up a set of ls6 heads and go to 9.6:1 CR

Also I am running Meth and yes I would love to buy a nice set of heads but I just don't have the $$ for it and I am just looking to get a little more out of the car.

Rickys S/C Z28

iTrader: (13)

the more compression(safely) the better in my book!

SteelmanLS1

iTrader: (1)

Granted I don't even have my Forged 347/D1SC underway yet.

But the past 2 weeks I have did NOTHING but research on heads for my build.

These (on the cheap) I think would be a Great head in your case. http://www.texas-speed.com/shop/item...d=134&catid=40

They were my original pick for heads, but I decided mine wasn't going to be a budget build and I decided on these heads for my 347 http://www.texas-speed.com/shop/item...d=135&catid=40

dschmittie1

iTrader: (64)

My question is more of what CR should I shoot for changing heads. I don't think that I want to go down to 9.0:1 but I could really turn up the boost then

SteelmanLS1

iTrader: (1)

Those heads are 72cc chambers I believe.

Not sure where that would out you, but anyway from 9.0:1 to 9.5:1 is good CR.

Some people prefer Less CR ratio, Some people prefer More CR ratio.

I have seen anywhere from 8.3:1 to 11.5:1 with a Forged 347 with D1SC

TurboAv

iTrader: (6)

If you want to get the most out of pump gas then go lower. Since it sounds like you are planning on using meth I really don't think it matters for you. I don't want to use meth so my 370 is going to be right at 9.3:1. You may have to repulley the blower anyway if the new heads flow better your boost will actually go down.

dschmittie1

iTrader: (64)

Yes I am currently at 9.2:1 with my stock heads and I am running Meth for Safety net and the extra power. The 72 cc heads would put me down to almost 8.8:1 so I would mill them to about 70 cc to be around 9.0:1 or I am debating getting 64 cc heads that would put me around 9.6:1

I already have the 317 72 cc heads so I am debating just getting them milled and ported and running them. Also I know that I will have to repulley the blower no mater what I do since I am searching for a little more power