I am putting a 56 GMC body on a 69 C10 Chassis.
The 69 is one inch longer than the original chassis
I purchased a almost "Rust Free" bare cab on Ebay form a guy in Mesa Arizona
We had to add about 2 1/2 inches to the end of the frame for proper bed placement.
Click on the picture for full size image.
Scott (AKA: Cadman) smumfor@yahoo.com