I recall that for the Fluidamper you use a small block bolt. Much longer than a stock BB bolt. I switched to ARP bolts and I think their BB bolts are a bit longer than stock but can't say for sure.

67 Coronet 500 9.610 @ 139.20 mph
67 Coronet 500 (street car) 14.82 @ 94 mph
69 GTX (clone) - build in progress......