Newer serpentine system and a.c. compressor

https://www.forabodiesonly.com/mopar/threads/la-to-magnum-parts-list.501473/#post-1973622428
https://www.forabodiesonly.com/mopar/threads/magnum-serpentine-belt-on-a-la.500493/#post-1973601928
I don't see it mentioned in either of those threads, but the Magnum heads have bosses on the end of them that LA heads don't have. Because of this, mounting the tensioner could be difficult on an LA.

Also, the truck PS bracket bolts to a boss on the block that either doesn't exist on LA blocks, or isn't threaded (can't remember which).