I had a set of heads redone recently and had them cut .020. A friend asked me after I had installed them if that was the first time they had been cut. I hadn't even thought about it but I know that I'm not the first guy to have work done on them. When I got them they had a new valve job but had been sitting and were rusty. Is there a reference point on the heads, like the flat area where the head bolts seat where they could be measured from to tell how much has been taken off them? Dave Berryo No:
One hint that the heads have been previously cut a fair amount....your intake bolts would most likely be quite misaligned with the bolt holes. Also, if you had .020" removed from the deck surface...make sure to take the same off the intake side of the head, to compensate.
About the only thing I can think of is to have the combustion chambers cc-ed. Someone correct me if I'm wrong about the exact number, but I believe you will lose around 1 cc for every .005" that the heads have been shaved. For example, suppose you have '71 heads with casting #1237661. The original chamber size for these heads is 71cc. You shave them .020", so, .020 / .005 = 4cc. Now the chambers should be about 67cc. But suppose they only measure 65cc. Then they were probably cut an additional .010" once before. It's not perfect, but it will be pretty close. Here is a link to info on heads and chamber sizes: http://www.atlantabuick.com/CastingNumbers.htm Larry
I thought you'd take half (.010") off of each head...? There's got to be a straight measurement out there somewhere...anybody???
I take half off the intake face as per the Buick instructions. Same if you deck the block, the heads intake face or the intake need to be shaved or it will sit way up....there is an actual calculation but I have found that half is just about perfect. You can always take a bit more off if needed..pretty hard to put it back on though. later Tim
