if the FE ones are the same below is the part numbers for them if one wants to hit up ebay or their local dealership to check for availability.
'58 to '59 - 332/352 - C0AE 6881-A
'59 - 430 - B8E 6881-A
And the bolt adapter to block is a 5/16"-18 x 1 1/8" and its part number is 20406-S8