Damn good info

I think the biggest advantage for a Magnum is when comparing a high mileage 5.9 to a high mileage 360. Almost any year 360 is going to be a low compression smog motor that has worn out rings and cylinder walls. The Magnum on the other hand has been run on EFI it's whole life and the cylinder walls will probably still show cross hatch and started with a much better compression ratio to boot. Put the same cam in both, figure out springs (they both will need them) and a decent 4bbl and the Magnum will almost certainly smoke the LA.

Rebuild/fresh one or both and it is a different ballgame. At that point it almost comes down to whether you want to run shaft rockers or not.