manual brakes. i hope i dont sound like a moron but im learning....im far from a motor guy. one thing i was thinking but not sure if its an issue. there's a large port coming out the back of the carb, i have a rubber hose going from that port to the breather on the driver's side valve cover. i think people with power brakes plug into that port dont they?
Post a picture of that connection at the valve cover. The hose should have a pcv valve, not just a breather. If it goes straight into a breather it is acting like a huge vacuum leak.