Hello, I am trying to restore my 1983 El Camino SS. I was wondering if anyone would know if there is a way to get reprint of my factory r.p.o. codes? I have purchased a reprint of the dealership invoice from the G.M. heritage center which told me the important things. Like the Z15 Super Sport package, LG4 305 engine, air conditioning, comfort tilt wheel, intermittent wiper, cruise control, etc. However, there are things that were not on it that I would like to know. For example, what rear axle ratio was installed at the factory. When I bought the truck, it had a open differential with a 3.73 ratio. The factory performance ratio was 3.08 and the basic ratio was 2.41 for that year. However, my books say that there were multiple gear ratio options that could be ordered ranging from 2.14 to 3.73 with open and positraction differentials. I want to make it stock, but I don't have the r.p.o. sticker from my glove box for reference. I have tried going to a few dealerships but they say that they can only call up information from 1990 production year forward. I would have to think that there is a way to retrieve the r.p.o. codes from G.M. or the factory that assembled the El Camino if it is still open. I mean, I'd think they would keep records of they're parts for accounting or safety recalls. If anyone has an idea of what I can do, I would appreciate the help.