I'm building up my motor and trying to figure out how much I need to mill to get a final CR of 11:1. bottom end is staying stock, just being refreshed. head is reworked and i think the only thing that will affect cr is the deshrouding. I'm going with crower stage II cams, skunk2 high comp valves, skunk2 valve springs/titanium retainers.


Using some basic calculations I figured that milling it .035" would get me just about where I want to be.

.035 X 2.54 = .0889 cm
3.14 X 4.35^2 X .0889 = 5.2821408
539.25 - 5.2821408 = 533.967859
53.925 - 5.2821408 = 48.6428592
533.967859/48.6428592 = 10.9773123
or about 10.97:1 CR.

My question for those in the know... how much if any will the Skunk2 High compression valves increase the compression? I've seen some posts where people say it will increase compression ration .2-.3 but have yet to confirm it with any reliable source. .2-.3 sounds high, but I assume that they raise the compression of the chamber to some degree as they are flat w/no dome, therefore decreasing the volume of the chamber.

I'm not planning on building the block, and likely won't for a year or so. I am switching to a manual tensioner for the timing belt. I will have cam gears so that I can time it properly.

Let me know if I'm looking at the correct amount, or if I'm horribly wrong. thanks