the 1990 mazda 2.6 is a mazda motor based on the mitsu design. Go to B2600.com for more info on it and our 2.6 mitsu motors. Mazda did run the mitsu 2.6 in 88 and 89 - the 5 spd tranny has a removable bell housing that allows the use of the RX-7 or other trannies to be bolted upto the truck 2.6. Not sure if it is a good id.ea to swap as intake / exhaust are swapped