Hy Joseph_Y, that depends if you want to maintain your six volt system or change to twelve volt at the time of transmission replacement. If you want to remain six volt you'll need a 139 tooth flywheel and a six volt starter for a 54 through 59 bellhousing. If you want to change to twelve volts, you'll need a 168 tooth flywheel and a twelve volt starter to fit the same bellhousing, hope that helps.
