I bought a 59' f 100 PU. The engine is a straight six 223 (?) with a 2 stud valve cover. It has an electric fuel pump which has quit working. I bought a mechanical fuel pump. The problem is that the only way it will mount is upside down. The wide part of the mounting flange and gasket normally point down on the 59 fuel pump but is reversed on the block. Looking in the Mac's catalogue the only two six cyl. Fuel pumps that have the wide part of the flange on the top are the 48-51 F1 thru f3 which has a glass fuel bowl and the 78-79 300 f100-f350. The pump lever on the 59 points down and on the 48-51 points up. On the 78-79 it appears to be straight and maybe uses a push rod. There must have been some kind of swap. I'm not sure the block is even a 223. although the head must be. Where would I find the I.D. number on the block?