vacuum 307 L chevy
 

I replaced my carb on my 1971 chevy 307 with a 1973 carb there not exactly the same the 1973 has a threaded hole in the back side closest to the firewall near the base of the carb does anyone know what this hole is for and if i can plug it also there are more vacuum ports on the new carb

Welcome aboard !!!!!! :thumbup:

moving to engine forum

The threaded hole on the back side of the carburetor (I assume its a quadrajet) is for the line to the power brake booster. You can plug it if you don't have power brakes.

The three ports on the front of the carb are usually the PCV valve (larger diameter line), vapor recovery canister (usually on driver's side), and line to the vacuum advance (probably ported vacuum, but might be manifold).

Bruce

thanks bruce
 

wow you rock vacuum was the easy part the hole however had me stumped i do not have power brakes so now i feel better about just plugging it thanks man