I was wondering. would a old school 360 bolt into a 98 dodge ram? I have a 5.2 (318) in it now. but I have a 70's 360 sitting around that would be fun to install!!! I was thinking about swapping the upper of the 5.2 to the 360 and getting a 5.9 ECU.
Besides what Bob mentioned, you'd have to deal with the LA engine getting oil to the Magnum heads. Then there's the balance differences (torque converter and harmonic balancer) between your 5.2 and the old 360 (and for that matter the still different Magnum 5.9).
Consider a V-10 if you could find a donor truck with one.
You would want the whole parts truck for this swap. If you swapped your 5.2L into the donor, you could make both of them a running truck after the swap. You would need the time and the tools.
The DMV has a form to register a modified vehicle that is different than the VIN, depending on your state.
Use AMC lifters that are meant to oil through the head. Comp Cams sells 'em when you buy an aftermarket cam from them. Use hollow pushrods.
IIRC, the main difference between the LA block and the Magnum block is the oil passage. The vital dimensions for the crank, rods, bore, stroke are the same with the LA 360. The other LA engines are not the same though.
I wouldn't be surprised if there's some kind of tone ring or something on various Magnum motors, but I do not have extensive experience with them.