I installed a factory GM longblock in my 89 S15 Jimmy. I purchased from a local GM dealership. Installed it myself and returned the core back to the same dealership. I have over 70K on the long block and it runs great. I followed the instruction sheet to the letter. The only issue I had was that when I started the engine the first time I shredded the serpentine belt. I did not have the Power Steering Pully co-planer with the rest of the pulleys. If you need any warranty work any GM Dealer can do the work. I also installed a GM Factory Remanufactured Transmission. There was no sheet metal (Valve Covers, Timing Cover, Oil Pan) with the long block. There is a special tool to install the oil pump pick up tube into the oil pump without damaging the tube. AutoZone has it as part of their loan A Tool program.