using mechanical pump?

couldn't a cam from a '86-91 (rollers) LA work? Yesbut they don't have much lift or duration.

On the comp specs or any cam manufacturer, look at lobe lift and multiply by 1.6 if using magnum rockers.
You end up with same duration as an LA roller with more lift. No need to go crazy on lift if stock OEM magnum heads are used. Piston to valve and retainer to valve guid e seal clearance needs to be checked depending on your combo.
Ok, so if one was going to drop a 360 mag from a truck into a older car, and was shooting for a "similar" motor like the 300 horse power crate motor, what cam (part #) would you order to have the mechanical fuel pump eccentric? Is there a cam that would run as smooth, work well with stock magnum valve train, and perhaps add an extra 15-20? Say, a 320 horsepower 360 magnum?