Change in plans... Anybody used a "retro-fit" roller cam in a Magnum?

I figure if I'm going with another engine it might as well be a 5.9L. 5.2s are cheaper and more plentiful around here but not by much and I'd rather have the extra torque than fuel economy. My Duster is more of a weekend-warrior road-race type build fyi.

I have a set of Hughes 1110 springs and their retainers, last I checked there was at least .560" clearance to the valve seal on the guide.