I have been slowly working on building a 31 truck. I bought just the cab, box and frame from a gentleman who started on it over 14 years ago. It had been sitting for the past 13 years collecting dust. The only thing that was really done was a real nice 4 inch top chop. All the subrails and interior bracing was pretty much toast, so the first thing that I did was to replace all that and get the body squared up. I'm 6'6" and with the top chop this would possibly be a problem, so I came up with a plan to lengthen the cab 7 inches. Hopefully attached are photos of before during and after this procedure. I've worked on cars most of my life and this is the first time that I have tried something like this. So far it seems to be working out OK. Once I'm happy with the cab back, I'm going to try and install suicide doors.