My 73 original intake has TWO plugs... one in high plane side, and one in low plane side... blocking the heat passage will kill choke operation... not that you'd need it in warm climate. If the 'unplugged' hole on the low plane side (driver's side) actually leaks exhaust into the intake, no wonder the fuel boils... but every other cylinder should show different color on plugs, as the hot exhaust gas would vaporize fuel and cause 'lean' mixture to enter cylinders on those runners..
Not know if intake can be reworked like Eddy...