After writing the Napco 4wd Chevrolet Trucks article, I was going to do a lot of research into a more complete article. I do not have to. The Napco 4×4 website has a NAPCO History section that has more information than you will ever need to know about the NAPCO conversions. Why re-invent the wheel? Take some time to wander around their website. It is very easy to loose a few hours!