Roller LA cam in a Magnum?

Indeed-always a good idea. Ran into issues like this with SBFs with the pedestal mount rockers. They'd always wind up noisy because too little preload.

Yes. I went with Crane's conversion kit,and Comp's 1.5 rollers. Forgot about the 1.6 ratio,pegged the springs too tight at .550+ lift. (Oops!) I prefer adjustable valve train anyway, lol.