This truck is 1965 Chevrolet Crew Cab C 30. I just competed a full custom rebuild in December 2012. Chevrolet didn't make a 4 door truck in 1965. The four door conversion is aftermarket. It was done by Armbruster-Stageway, a limo company in Arkansas that did some crew cab conversions back then. I can't find any information regarding how many conversions they did, but you don't see very many around anymore. One article had stated only a couple hundred a year were done. My understanding is that these trucks were primarily converted for the railroad or Forest Service. Additionally, I upgraded the engine to a 12 valve Cummins Turbo Diesel with an Allison 1000 automatic transmission and a divorced mount NP 205 transfer case. Also, the truck was converted to 4 wheel drive. It has late model axles (Dana 60 front and GM 14 bolt rear) and 4 wheel disc brakes.