64-65 heads and valve covers are entirely different from 1966 and up. On the head and the valve covers of 64-65s near the location of were the distributor would go in the block is not straight across but is indented. All other factory heads are straight across in this area. There are many 1964 heads, and I believe the factory 64-65 valve covers were chrome, mine are chrome anyways. My 1964 heads are the earliest heads cast for a hemi.