Are all 455 heads between 1970 and 1976 interchangeable? I have a 1970 and need to know which years will work. Are some years better than others? do later ones have hardened seats? THANKS!
I don't know all the differences, but if you're looking for hardened seats I think everything made in the year all cars switched to unleaded gas will have them.......I think that was '75, weren't cat converters mandatory beginning in that year? :Smarty:
The earlier heads would be better from a performance stand point. The 75-76 heads have an open combustion chamber design, having a volume of somewhere around 78cc. Earlier heads will flow better, and will yield a higher compression ratio due to a smaller combustion chamber volume.
