Adjustable Fuel Pressure Regulator 1.5-8.5 PSI

The carbs on B18s and B20s are very sensitive to overpressure, which is compounded by fuel heat-soaking and expanding in the fuel lines routed over the hot parts of the engine and in the carburetor itself in direct contact with the hot intake manifold. If you have problems with fuel overflowing out of your float bowl, it could therefore be a pump overpressure issue, a fuel heat soak/expansion issue, or a combination of the two. 

Whatever else you do to fix this problem, we definitely recommend insulating the carburetors from the intake manifold with phenolic spacers (see Recommended Products below) and rerouting the fuel-pump-to-carburetor fuel lines so they're further away from hot engine parts. If you're still having fuel overpressure issues, you can also try this inline adjustable fuel pressure regulator.

Replacement mechanical fuel pumps for these cars (including the ones that IPD sells) output between 3.8-5psi, which can be a little higher than the 2-4psi DGV progressive carbs seem to like. Made by carburetor experts Weber, this adjustable fuel pressure regulator has a range of 1.5 to 8.5 psi, allowing you to really fine-tune your fueling.