Roller LA cam in a Magnum?

To answer your question yes. The 89 roller cam has the long snout for fuel pump eccentric. Also the lift specs for the 89 roller are based on 1.5 rocker ratio, putting it in a magnum motor with 1.6 ratio will result in a poor mans low duration higher lift cam in a magnum motor. Make sure you check piston to valve clearance with any cam change. Also any listed hyd roller retrofit LA cam will have the long snout and will work in a magnum engine using a LA timing cover.