There were actually several because there were a couple different versions of the bolt. The early 256-14991-00-00 version had a screwdriver slot across the head. These came on carbs up to about '77 .....
The plain head bolt used from '78 through '80 has a couple different numbers, don't know why. They would be 1A0- or 1A8-14991-00-00 .....
The plain head bolt used from '78 through '80 has a couple different numbers, don't know why. They would be 1A0- or 1A8-14991-00-00 .....