Ok I will be putting my 390 bigblock in my 77 F-150 pretty soon. The motor has been completely rebuilt, new lifters, cam, seals/gaskets, timing chain, etc etc. It was run about 6 hours after the rebuild and hasnt been fired up since. Now its a HiPo model and has stock everything...I want a slightly hotter cam about .530i/e lift. With all being new would the factory 390 lifters be compatable or do I need to get new ones. I'd think they could probly work with a fairly large cam anyways but i'm not quite sure.