Something to check would be cam timing. Almost everything in the world has the dot on the cam gear and the dot on the crank gear lined up and facing each other at 6:00 on the cam gear and 12:00 on the crank gear. Not so on a smallblock Mopar. The dot on the cam gear should be at 12:00 with the crank gear dot also at 12:00. They won't fire if they are 180 degrees off. Hope this helps.
