what's different?
Petcock: some use a banshee petcock so it has a real on/off. If the stock petcock runs fuel fine on prime, I plug the vac port and install a on/off valve from auto parts store along with a filter. I put the stop valve as close to the carb as possible. I let the carb can run dry when done for the day.
Chain: smaller chain (I use #40 with 438 sprockets) will roll much easier. I pushed my 80's with 1 finger.