Here you go.
http://chevy.oldcarmanualproject.com...resto/5070.htm
http://chevy.oldcarmanualproject.com...51ctsm0202.htm
I'll suggest buying one of these.
http://www.classicindustries.com/pro...ts/tm1047.html
It's worth it. It has in depth dimensions on everything related to the 47-54 trucks. The Frame dimensions it has are for a 54/55 1st series, though. The only difference is the amount of kick above the rear axle.
Chris