ok i have in my 67 coupe a 1976-1977 351w i have a vibration and am tinking it is in the flywheel so i got the flywheel part number and am hoping someone can let me know if it is or is not the right one

flywheel # is c6ze6380a,

this flywheel has the small weight and it is drilled both on the weight and 180 degrees frim that drill mark, i spun the flywheel and it does not end up with the weight down like every shop tells me it should, but that could be because i am spinning the flywheel on a screwdriver and it is not that easy to spin it!