Had the same problem on a 1948...tried all the fuel pump stuff....my truck would not go up any kind of hill....there was an old rag floating around in the gas tank that someone had used in place of a gas cap..it drove me nuts until I took the tank out. On my diesel tractor some kind of bug cocoon fell in and did the same thing...now I always filter my gas and diesel...fuel pressure will as give you some kind of indicaion...Steve