Alternator

Welcome to our world. Be sure the new one matches the old one. If there are any spacers in one of the mounting holes, you may have to tap it one way or the other to center it.

Also, be aware that this is the worst design generator GM ever dreamed up. It is common to go through four to six of them in the life of the car. What many professionals are finding out is to reduce the number of repeat failures, you should replace the perfectly good battery at the same time. These generators develop huge voltage spikes that can destroy the diodes and voltage regulator built into the unit. As the battery ages, it looses its ability to dampen and absorb those spikes. The old battery will work fine an a pre-1987 vehicle with the older, more reliable generator.