What's the max amount you can mill off a 317 (6.0) head? Also, is it .010 or .015 that you have to remove in order to lower the CC by 1 point?
Just wondering if there is any way to reach 66 or 68cc on a set of 317s?



Here is my dilemma;

I'm trying to get the best DCR ratio I can with the cam that I have. This is going to be a stock LQ9 with a TR230/224 111 cam.
Here is what I'm coming up with.


230/224 w/ 317s

DCR Ratio

72cc & .045 = 7.8 DCR <--- Obviously too low
68cc & .045 = 8.16 <--- Thinking about this, but is this still too low?
68cc & .040 = 8.26
66cc & .045 = 8.35
66cc & .040 = 8.46


SC Ratio

72cc & .045 = 10.36
68cc & .045 = 10.86 <--- *
68cc & .040 = 10.99
66cc & .045 = 11.13


If I can’t get the 317s to 68cc, my next option would be to go with LS6 heads correct?

 

BTW, here is my cam card in case anyone would like to double check my work.

 

Pretty sure that the 317's are a large chamber version of the LS6 and LS2 heads. You might be better off going with a LS6 or LS2 heads. Those are 62-64cc chambers, right? You could polish the chambers and maybe remove a little material to end up at 66-68cc's

 

Yeah I just got this info from Rich at WCCH

So it sounds like maybe getting some LS6 heads might be the way to go or else I'll be milling a lot and throwing off the Geometry.

 

You can mill however much you want its just a matter of p/v clearance with some cams. Where did you get those specs?
They seem to relate the size CC and then the amount to mill to reach desired compression but it doesnt say what motor its on, deck height, piston dish etc... all that info is need

DCR is mainly concerned with the intake valve closing on the comp. stroke so its sset by the cam, you need to know valve events to figure that

 

Whats the deck height of the LQ9?

I know some LS1's have their pistons abouve the deck. Same thing with the LQ9?

I'm trying to run the numbers in the DCR calculator I have.

 

Yep. -.008 piston DH for LQ9

 

I said its going onto a LQ9. I already entered in all the info needed to find DCR and that is what I listed.

I've got a DCR calculator and everything I need to know for it is listed on the cam card.

 

I put -.007 so I wasn't too far off.