H405CP versus stock magnum 5.9 pistons

I have both Magnum and LA cranks (stock) sitting here Good shape, and ready to go.
I can't speak for 360 engines, but for the 318, I know for sure, that the same crank from an LA crossed over to the Magnum years. I remember spending lots of time in a crankshaft book, when I built my 1st 318 Magnum. I might have to look into that, as it relates to a 360.
I have a good, machine shop polished '76 LA 360 crank (really my son does, but I can have access to) and I have 2 good, Magnum 360 cranks sitting here. One '00, one '01. Like I'd said, right now this is strictly a "bench race" exercise for me, for the moment// though I dunno what my son has in mind for his '72 land yacht Fury wagon. He was talking about taking one of my 318 Magnum blocks and making it into a 390, (318 with 4" crank) once he gets to that point. His other 72 wagon had a 440 in it (he has one of those from a motorhome, sitting in his garage that could go in) he wants an OD with 3.something gears/ and knows that a small block based engine, would be easier to run with that OD (probably would be a 518) This wagon is an original 360/727 car.
I have a Volare to finish, and thought at one time thatI knew exactly what engine I wanted to stuff inside, (318 Magnum with a 5 speed) but now "project creep" has sunken in. and I have more questions and parts hanging around, than answers. (which I thought at the time, I knew exactly what I wanted to do with that car/ not so sure I know anything these days haha)