the OEM cams in Magnum engines dont have the boss for the fuel pump (its electric in the tank) its shorter, so if youre gonna use a Magnum engine in the older truck with a mechanical pump, you need to change the front cover/belt system to the LA-style. I know theres a company that makes a conversion kit to use the serpentine belt on the LA engines-maybe its Schumacher? And if y'all knew that already, ignore me, everyone else does
and BTW-in case y'all arent familiar with my Lightning Slayer '96 Ram in my sig/smiley, I built this 408 Magnum (487 HP at the crank) for it last year:
68 Valiant 408 69 Charger 318 69 Cougar 351W 70 Torino GT 351C 71 Country Squire 351W 71 Road Runner 440+6 71 Satellite sedan 318 73 Duster 318 73 Challenger 383 77 Grand Prix 455 83 Malibu 9C1 383 84 Delta 88 403 87 Grand National 96 Ram 360 09 Crown Vic 10 Challenger R/T M6 15 Challenger Hellcat M6
the OEM cams in Magnum engines dont have the boss for the fuel pump (its electric in the tank) its shorter, so if youre gonna use a Magnum engine in the older truck with a mechanical pump, you need to change the front cover/belt system to the LA-style. I know theres a company that makes a conversion kit to use the serpentine belt on the LA engines-maybe its Schumacher? And if y'all knew that already, ignore me, everyone else does 
