[Beemer]

I have a Superformance MK III with a 351 stoker with 2 Edelbrock 500 CFM carburetors. It also has an electric fuel pump. It has a running rich problem causing the spark plugs to foul I am trying to solve. After speaking to a number of folks, one item brought up is when I open the gas tank filler, there is a lot of back pressure whereas my friend with the same car except he has a Roush 427R with a mechanical fuel pump has no back pressure when opening his gas tank filler. One person suggested I may have a clogged breather causing the pressure leading to the problem. Another person said it is just a carburetor issues and need to set the mixture. Another person said I need to put a pressure sensor in line to ensure the fuel pressure doesn't exceed the Edelbrock requirements.

Any thoughts?