Magnum motor with Mechanical fuel pump ?
Good plan. Magnums are good engines. Basically, you want the entire front off of your LA. Timing cover, water pump, pulleys, alternator, power steering pump. All my pulleys lined right up.
Magnums are externally balanced, so you'll need a weighted harmonic balancer and you'll need the Magnum flywheel. Oh, and a neutral balanced torque converter.
I've been running an electric fuel pump for years but over the winter, I'm going mechanical. I bought an eccentric from a FABO member, just need to buy the Hughes adapter and a new mechanical pump.