How much would you need to mill a set of 317 heads to bring the combustion chambers down to 68cc?

 

say the combustion chamber is 72cc mill them .030 and it brings it to 67cc

 

Where do you think that would put the compression ratio on an LQ9, around 10.8:1ish? I'm looking for 10.5-10.6:1

 

Bump, looking for 10:5-10:6 compression out of an LQ9 with WCCH 317's. Any guess on what size pushrods I'd need (I have a pushrod length checker, just looking for a guesstimate)

 

Hey Billy,
Our standard size 317 chambers end up at 74cc unless additional milling was done by us. To get to 68cc you should mill them .036" which will put you in your desired compression window. Feel free to call me at the shop if you have any questions.

Richard

 

Thanks Richard I didn't have them milled when you first built them for me, but now I'm thinking that I might want a little more compression from my set-up. I'll probably call you soon to pick your brain

 

Not to jack the thread, but what is the actual static compression after milling the 317's .030 on an LQ4? Around 10:1?

 

I spoke with Richard at WCCH this week, AWESOME customer service as always I can never say enough about how great he is to deal with, I can't wait to get my trans swapped so I can start on my LQ9 and get these great looking WCCH StageII's bolted on

Thanks again Richard!!

 

Thank you for the compliment.
Good luck with your head swap chief. Let the tire smoking begin..........


Richard

 

What kind of HP/TQ gains are expected with increasing the compression ratio a half a point or even a full point? I know the cam determines powerband, but does a change in compression ratio alter it?