I use an electric fuel pump which has 2.5 pounds of pressure. That is truly all you need with a 216, 235 or 261 unless you've modified it to drink lots of gas. There are at least 5 reasons a Rochester B will leak fuel. Unfortunately only a couple of them are easy to fix, but yours sounds like more of an easy situation. I'd take the carburetor apart and check to see if the float is working and working freely (be certain it isn't binding on the float bowl). Blow air (with your mouth) in the fuel inlet and lift the float so that it reaches the point where it will close the fuel valve (some call it the needle and seat). Look at the fuel inlet orifice. The hole in the seat if you prefer. The cheap rebuild kits all have very large orifices...when I was doing the Rochester study, I found 3 different sizes. (see image below) If you have the large one, your float & fuel valve probably can't keep up with it. That is to say if your pump is outputting 6 pounds of pressure and you have that large orifice, it isn't going to be easy for your float to regulate things. The fiber washer for the fuel valve is generally as good or better than the brass one in my experience...particularly with an older carburetor. It should have been in your rebuild kit. If fuel is pouring out of your gasket (between the float bowl and air horn), something isn't working with your float and fuel valve. Please let us know what you find.
~ Jon 1952 1/2 ton with 1959 235 | T5 with 3.07 rear end
