welcome to the shop Pete - robin58 has the right idea, look around and compare ... check out the gallery here to for visual reference
7500 for any truck that needs a total cosmetic resto [body, interior, wood] sounds pretty spendy to me, and will be worth it's weight in gold by the time you finish it .... and 57 didn't have a floor shift 3 speed, so if it's not actually a 4 speed, it's been modified there
Bill