I know this thread is a little dated, but it might help someone. 37-40 216 flywheels have a larger diameter opening for the crank than the other years. I have a 40 1/2t with this larger opening. I don't know if it is just truck of that era or cars also. If you are swaping to a 235 in these years, you will need to find a newer flywheel with the smaller opening.
