LA or MAG

I have a 360 in my car j heads ld340 intake with a camshaft designed for a 4x4. The
Heads are prolly the worst looking heads i have ever seen (casting flaws in the exhaust
Ports) it has pretty low oil pressure so it will need some work this winter. I have a 451
Project in the works right now,but it will be a bit before i finish it. I came up with a 5.9
Magnum motor that has a messed up piston ,cylinder wasnt hurt.

Now my question. What should i do here. Freshen up the 360 start beefing it up. Build the 5.9 or just concentrate on the big motor. What am i looking at, doing the mag motor.
Can i use the rotating assembly out of the la for the mag(for converter balancer issues) i
Would like to build the mag motor for the reason of it already being a roller. I see where
Everybody puts the mag heads on the la motors. What are the advantages/disadvantages
Of both small blocks.

I appreciate you guys and all your wisdom