Im pretty much a beginner when it comes to engines but i have the general idea what is going on.. I have a 1971 400ci ..Im trying to replace my fuel pump which came off fine but neither it nor the new one will go on. the lever arm can go all the way in when the pump is flush to the block but the pump is about an inch below where it should line up. It seems like the cam is in the way or something. I checked and I didnt see a pushrod in the way so I have no idea what is going on and its really frustrating. Id appreciate any help thanks.