I was lucky enough to find some 915 closed chamber mopar big block heads on Ebay recently to use on a numbers matching 440 Magnum from 1967. I am planning to hop up this motor for a Charger restoration. I want to know what are the biggest valve sizes that will fit into these heads, since they need new seats and valves anyway. The extra valve size will help with the short side radius and will improve flow considerably once I port the heads. I want to focus on making the intake valve as big as possible if that matters at all.