Chevrolet was constantly improving these cars each year. During this time engineering was advancing at a very fast pace. The customer also would have to be convinced that this would work and work well before buying such a car. Chevy and Ford were pushing the limit as they competed. Look at the ads on the net for these old cars to see just how fast improvements were coming. The group of cars from 33 to 36 are in a constant change, some even have half year changes. Where some of the parts will fit on they do not function the same in performance. The 1932 car group and somewhat back are of a different group entirely. To mix parts on these cars requires major structural changes in some cases. What you are proposing is a good way to ruin a good antique, and devalue it. Repair of what is original can be done.