74 duster elelctrial help

The lifters were not hurt by piston damage. That would have bent valves, damaged pistons to the point that you could SEE the valves hitting, and or bent / broken pushrods and other valve gear.

If it wasn't broken in, perhaps the lifters had been used/ mismatched to lobes, or oil additive was not used. There are threads on here, folks are having problems with flat lifters. "May be" a metalurgy problem, I do not know