The military cam has a lobe for a fuel pump and the block has a boss for a fuel pump, but no hole. It used to be common to cut a hole and tap for bolts using a fuel pump gasket. But I even retrofit civilian engines with electric fuel pumps because I don't like mechanical fuel pumps. When a fuel pump fails on a GMC, it is quite common for it to squirt gas on the cam and wash the lubrication. I set me fuel pumps at around 4 psi. Thats all I need and it relieves a lot of strain on the needle and seat. The only fuel pump for 6 volt that I have been able to find lately is a Carter which puts out about 8 which I consider to much. Facet, which I prefer no longer makes 6 volt, but they do make a 12 volt at around 4 psi.