RPC Aluminium Carb Adapter with Studs & Gaskets (RPCR2067)ALUMINIUM SQ TO SP ADAPTOR Square Bore to Spread Bore (AFB) Part Number: RPCR2067 Mounts Holley, AFB or Edelbrock 4 BBL square bore carburetors to Quadrajet spread bore carburettor flanges. Can also be reversed to mount Quadrajet carbs to square bore manifolds using (2) 4. 400" studs (sold separately). Made out of high quality die cast aluminium with a 0. 850" thickness. Kits include gaskets, mounting hardware and vacuum port plug. Specifications: 0.