You have two problems. The 89 motor and the extra weight of the 2500. If its a 2 wheel drive you might get away with changing the gear ratio. You can put a vortech motor in it but you will have to change the ECM. And you would be better off using a "stand alone one" like the street rod people use because you don't have an electronic shift transmission or OBD-2 on the 89. A friend of mine has the same truck. I put a set of vortech heads and 4 barrel intake (all bought new from GM) and it wasn't to much money. He's happy with the truck now. Just something to think about. The vortech heads are a cheap HP bolt on thing. I'm sure your happy with the better brakes now. Good Luck.