Plan on going with a mechanical roller cam on my sm 408.Have heard very good results from racers using the Howards retrofit lifters ,but most of them are gms. Any experience with these ,will they drop in without machining? The cam will be relatively mild around 257i 265 e at @.050 around .600 lift. Its a pump gas (10.01)race only ,no street. Made 470 hp with stock eddys.Now eddys ported by Modern, Victor intake and a halh a point more compression. Looking for 520to 540 hp.

Use a hydraulic roller grind and then put solid lifters on it.

Lash it at .002 cold and forget it.