There is no pressure regulator on any carb of which I am aware.

Pressure cannot be added between the front and rear bowls. As they are hooked together in parallel each sees exactly the same pressure.

A metering block can only reduce pressure, not add. If there was something wrong with your secondary metering block, that side wouldn't be getting any fuel. There is an exception to this, and that's if you have a secondary power valve with a ruptured diaphragm, fuel will steadily run into the main circuit.

When you say overflowing what do you mean exactly??? Where do you see the fuel coming out?

There is a gasket between the float setter hex and the bowl. There is another smaller gasket under the lock screw. These have been known to leak.

R.