i dont think it will make a difference, the heads for both the 5.2 and 5.9 are the same, at least as far as my understanding of them goes. in 92, the LA 318 engine got new heads, intake and exhaust manifolds, and fuel injection. in 93, the LA 360, got the same parts. both engines were then labeled Magnum engines. same went for the LA 239 V6, now the 3.9
they are exactly the same; 2 casting numbers cover all V8 Magnums only diff is what plant they were cast. these heads are the same and both numbers were used on both engines; I had one 318 that had one of each.
But the biggest difference is that the LA expects the oiling for the rockers to come up inside the block, and it lubes through the shaft mounted rockers.
Magnum heads expect the lifters to pump up through the pushrods, and lube the stud mounted rockers that way.
So if you put LA heads on a Magnum block that doesn't have the oil passages drilled, the rocker shafts are run dry and it might run 1 or 2 minutes. Maybe. If you're lucky.
The head design also shifted the angle of the intake manifold bolts, and the Magnums also have more valve cover clamping positions to help slow down the valve cover leakage the LAs were prone to. (It was supposed to stop it, but not really, alas.)
Magnum heads can be used on LA blocks, !IF! you use the proper lifters and pushrods.