vivivivivibration

OK your flywheel will only bolt on in one position so that is set. The front dampers can ware out and the timing mark slot moves to a different position around the crank, the rubber in it can go bad after 50 years. Can check by having someone put their thumb on number 1 spark plug and start rolling it up to Top Dead Center, you should feel the compression stop building at this point, see if the damper is lined up to TDC with the timing cover marks. If they are not anywhere near the damper outter ring may have moved and needs to be replace with a new damper. Rock auto has them, ebay too. If this is way off then the ignition timing will be way off too.