Rebuilding your own units is a great choice. I,ve been doing my own GM,s for many years. Like the guys say the parts are readily available from a parts store. The quality is often better then what you get in a reman. The parts like brushes & diods on the older alt,s with external regs. are getting a little spotty. Some can,t supply them anymore. The brgs. are all the same. There are some rebuild kits for starters but you don,t need them.