I have a 1995 chevy silverado swb single cab thats 2wd. I have a chance to get a 1989 chevy silverado swb single cab thats 4x4 but needs a motor. I am fully aware that in 95 they changed to obd2 and in 89 they had obd1. The 89 has all of the wiring they just unplugged the motor and took it out, the harness isnt cut. I was wondering what would i have to change on my 95 motor to just be able to drop it into the 89 chevy. They both have automatic transmissions only difference is year and 2wd/4wd. Thank you.

 

I believe 96 was obd2.
95 motor should drop right in to 89 truck. Only the connector where you plug in the code reader is different in 95, it has obd1 computer with obd2 connector, but the wires don't go to the same ports