Leontine. Welcome to the stove bolt. thats an intresting looking little chevrolet truck youve got there. Am curious is the body that you took off common. I was trying to determin if that was a suburban body originaly and if it had modifications to the rear of the roof, was it an ambulance or what. I was looking at the cab roof line and wondering if it would match a regular cab roof line. I think if I were in your situation I would try to find another 3100 chevy truck 1949 thru 1953 to look at and compare the way the cab is mounted do some measuring make comparisons and try to determine if I needed to replace the whole cab, or try to install a rear pannel.......Ronnie