Crowers will live with high spring pressures and are reasonable cost Comp 829-16 lifters can't take the big pressure long at all When you send them back to Comp for the rebuild service ( thinking you will save $$ ) they send back incomplete sets and tell you some were shot--then you are buying a couple of pairs at big $$ and the good deal goes out the window---lots of folks have run Comps without problems but a serious race engine needs the Crowers--on SOME blocks a little grinding or machining is needed--good guy to ask is Todd Marsh 336 752 2879 He told me he had Crowers in stock for an unbeatable deal