Hydraulic Roller Lifters

340sFastback said
What he said. You need to get a "retrofit" roller cam set up for a '77 block. This is because the older blocks have shallower lifter bores and the older blocks don't have the mounting bosses to hold the bracket that keeps the lifters located.

Also cam must be ground for roller lifters to work correctly. You can't run a flat tappet cam with roller lifters.

All of the above regarding the lack of mounting bosses...aside from which, that cam is pure junk. Waaaay too much seat timing and a very mild lobe. Duration @ .050" is plenty for a street 318 (maybe a little too much for a pure street car) but not enough lift given the duration.