Well back in the day before custom pistons were available, the guys would use and modify the GMC pistons, since one of those engines already has the same bore size as the 235 Stovebolt's and already had the GMC pin size, so going custom isn't necessary but is an option is someone wants to. But without divulging too much info that is in the Stovebolt Performance book I mentioned earlier, it show's and explains how all the swapping is done without breaking the bank.
