When purchasing a new cap, what do you tell the parts store? In other words, what year make and model do you buy for since the cap is obviously not for a 1947 Chevy?
Any cap and rotor for a 56-61 car or truck with a 235 engine should fit. The same cap and rotor was used on the 56 and newer 261s, but even mentioning that engine to the average keyboard jockey at the local parts store will give him a case of hives! You'd have to specify a C-30 or bigger truck to even find that engine listed for it.
Jerry