So far as the Courier / Mazda thing, the FOUR banger Mazda pu's were pretty much the same as a Courier
BUT the ROTARY powered Mazdas came with 4.11 rear axle, and the FRAME was wider, making them much easier to swap. Only problem is, I never really liked the front style of the Rotary
A former friend of mine shoehorned an Olds 350 into a Rotary chassis