I have my original q-jet from the 327 that came in my 67 chevelle. It has a big port at the base of the back of the carb. It is blocked off right now. Where did this go originally and what was its function?

Jim,
Probably for power brakes or possibly pcv if your vehicle was so equipped.

Thanks Bill. Car did not have power brakes and the PCV valve is hooked to vacume in the front of the carb. I can't remember, but could this have gone to a hole behind the distributor? I can't remember if the old 327 had that hole or not. I was thinking only the 283 had that.