Carb Spacer Question

Weeellll, It's not really "the small pattern", it's a spreadbore pattern manifold that you happen to have a square bore carb bolted onto.
Just get a Thermoquad spacer and you're good.
Fits Thermoquad Phenolic Carburetor Insulator Spacer Heat Soak Riser Mopar 1/2" | eBay