I have two Holly Carbs, but need more info on them. The only numbers I have found on them are:
RB4013-1 02-08 12R-10552 and the other one is

B0 531 06-19

What can you tell me about these two carbs so I know what to do with them. thanks

There should be 3 numbers on each carbs air horn(aka choke housing)

best bet is to call Holley theyll tell you exaclty what you wanna know, and give you part #'s for kits.

I have a book on holly carbs but i need the list numbers off the choke horn area