Holley Baseplate

Hello everyone. I need a baseplate marked 12r-4770b for my holley 80508-2 750cfm vacuum secondaries. I know that the later model 3310 and 650-800 double pumpers all use the 12r-4770b casting baseplate that I need so if anyone has any spare/parts carbs with that base plate, I'd be willing to purchase the entire carb from you as I'm sure I'll use the other parts too eventually. Thanks!