I am eventually planning on milling the heads on my 400 big block, and I am considering having them milled a little at that time to bring my compression up. The combo is a '77 block, .030" over, with Keith Black 240-.030 flat tops. They sit ~.025 below deck and give 9.0:1 compression with a .020 gasket, or 8.7 with a .040 gasket. My heads are rebuilt iron 452s. Reducing the combustion chamber volume to 78 cc would get me to 9.8:1 with .020 gaskets, and would require milling maybe .040" off the heads. .060" would get me to about 10.2:1 or so.
My question is this: how much can I mill them without requiring custom length pushrods or adjustable rocker arms?
My question is this: how much can I mill them without requiring custom length pushrods or adjustable rocker arms?