if nick is installing the motor he should know how to do it. i think there may be a bracket you might have to buy for the external oil cooler on the 91 motor, but that may be something that is included in the setup left on your 90 as well, i can't remember if it's a stock part that you need to do a conversion or if it's something required due to a physical difference. i want to go with that it's a stock part.