Isn't the height of the distributor cap and maybe the rotor different between 216 (and early 235) distributors and later distributors in 235s and 261s?
And, didn't the cam gear difference take place between 1953 and 1954, depending on the use/style of the engine? Maybe low-pressure 216 and the earlier 235s vs truck high-pressure 235/261 in '54 and car-235-Powerglide in '53?
