This Carb spacer didn’t work for me, but might for you

Slant Six One Barrel Phenolic Carb Spacer | eBay

Doesn’t have the hole for the PCV on the intake, even if you make the hole the carburetor bolts will need to be longer. But the passenger side bolt will rub on the carb body of a Holley 1 barrel. This was on my 72 valiant with stock 1 barrel.