Pat,

In your Compression calculation program, do adjust for any clean milling of the heads or block? Or is this just based on a bone stock configruation, no mill work done?
My heads and block have not been cleaned milled, so this would be very helpful to know.

Thanks,
Fred.

Originally posted by SS4speed:
Pat,

In your Compression calculation program, do adjust for any clean milling of the heads or block? Or is this just based on a bone stock configruation, no mill work done?
My heads and block have not been cleaned milled, so this would be very helpful to know.

Thanks,
Fred. Fred,
Not Pat here but,, you need to know the measured volume of YOUR heads, pistons & distance from the deck the piston is & dome or dish volume along with the gasket thickness to get an accurate compression number.
You cannot rely on any published volume number for heads or deck heights as they are a nominal number & you will find that the actual numbers can vary all over the map.
Heads are the worst as I have seen heads posted as 118c that are any where from 111 to 123
I have found most pistons to be very accurate in advertised numbers but it still doesn't hurt to check. ;)

Hey Mike,

You are right on, they are all over the place. I got one as high as 124 cc, and one as low as 114. In your opinion, how close should I have mahcine shop match the CC's? I would like to get them all close to 22, except the one 24.
I'm only guessing, but I expect that this has to add to the vibration of the running engine.

Thanks,
Fred.