Read the Allpar site first. The Magnum V-6 was a quickie solution for the new Dakota pickup because the V-8 wouldn't fit. They later found room and dropped the V-6. Since they just lopped off 2 cylinders, it wasn't an optimal V-6 design and had vibration issues. I see them often in RAM vans at PicNPull. Seems Mopar often used surplus parts in later full-size vans and campers. But, the fact that it bolts up to a 1970-80's 904 style tranny is attractive, though you then lose the crank pickup and thus modern controls. It sure looks at home in an A, though to use its tranny may require re-fabbing the car's tunnel (true for V-8 Magnum). The Magnum V-8 engines suffer cracked exhaust valve seats, which might affect the V-6 as well.
The 3.8L V-6 is a better design, having a 60 deg V angle, so much less vibration. It was used in minivans (my 2002 T&C), but a better source is the RWD version used in Jeeps. Some Jeepers deride it as "a minivan engine", which seems silly. The FWD versions may be missing some motor mount holes and the intake ducting may not work. Not sure what tranny the Jeeps used, but they long used Mopar trannys. Look for a 2WD Jeep. The 3.8L is still a push-rod design, so might still fit under an A-body hood, though the shallower angle makes it sit taller than a Magnum. Indeed, the rockers and shaft look like in my 65 383 engine. Speaking of that, get a later one. They added a rocker post to the head since early ones suffered cracked posts. The 3.3L is almost identical, but I don't think a Jeep version. The Engine Builder site has a great writeup on the variations.
