The 250-292 family of engines are more modern (e.g., a seven main crank, less weight) than the 235, but they certainly won't pass for stock. What will pass, except to the real experts, is a 261. I had one in a 1953 Chevy back in the late fifties - early sixties. At first I used the three-speed with the torque-tube, but later converted it to an open driveshaft (1941 Studebaker rear end) and a Muncie four speed. I've not looked into using an automatic. There is a 261 for sale on ebay right now.
A 1954 261 on ebay Several of the Inliner advertisers (Tom Langdon's Stovebolt Engine Co.,
Patrick\'s , Larrowe, etc. sell parts and speed equipment for the classic stovebolt engines.
An interesting historical article about the 261 is available, as is a link in the Tech Tips to the left.
