I bought a AC fuel pump on ebay buy it now. The number on the flange is 177S40503. It has the raised AC in the casting. The number on the box is AC 40503 with a small #6416712 on the top of the box. Joe lucia said it was the replacement for the 40433. I have a replacement Airex on the car now. Is this the correct replacement for my 1967 C-2 w/300 HP engine code HH? A friend also has a 40503 with 015R40503 on the flange and raised AC, the box is the same as the other pump. What is the difference in the flange codes and would one be more correct than the other? Thank you Dale