edelbrock carburetor flooding like crazy....

make sure you have an old towel handy in case you get a backfire then a fire starts... preferably not a towel soaked with oil.
if you get a backfire and you see flames start in the carb you can snuff them out with your towel.

also have a fire extinguisher.

ok now the safety part is covered, troubleshooting.

first... if you have an electric fuel pump you could be over pressurizing like someone else mentioned. carbs generally want 4 to 7 psi of fuel pressure. more than that and fuel will spew past the floats/needle valves.
some electric pumps dont have regulators. some do. but some that do regulate at 20psi etc. so if you have an electric pump, you should have a pressure regulator as well.

second, even if it's a mechanical pump it could be defective, over pressurizing the carb.

third, you could have stuck needle valve(s) like someone posted.

but again, having an old towel around to snuff out flames could save your car. dont screw around much with the breather off and take chances without a way to snuff out some flames.