beedo

iTrader: (28)

I am completely lost, I have a set of 317 heads I am thinking of selling. My question is should I mill them .015'' and get the compression up to 10.5 in my lq9 and run them, or get 799/243 heads and my compression will be 11.1ish I also cant figure out the chamber sizes, the 317 heads are 72cc but milled are~69cc with my compression being 10.5.1 but 243 heads have a 64cc(i think) chamber and my compression will be around 11.1. if my compression is about the same between the sets of heads and the 317's flow as well as the 243's why spend 500.00 on a set of heads I do not need? I am lookinf at 1/2 point of compression and I know the chamber size is bigger in the 317 heads but does that matter if the compression is close to the same? I am lost and need some clarification.

99 Blue Bird

iTrader: (3)

i would mill ur 317s. if u used 243s wich have 64cc chambers and a thin gasket ur cr would easily b over 11.1.1 but if you only want 10.5.1 i would mill ur 317s. and yes 317s flow the same as 243s.

mark21742

I'd keep and mill your heads. My guess is that you will be taking atleast 0.015" just to get you 317s true again (I've never seen a head that was used be true right after unbolting it)
I'd shoot for a total mill around .025"

I think its .006" mill for 1cc (if I remember right)