FUEL TANK INSTALLATION ORDER

Ah crap. That's what I get for buying **** too far in advance. If the 70 and 71 cars have the same quarters, and I am using the 70 filler pipe why does it not work? And, why would it work on a 1970 car? Trying to understand. I appreciate your input.
Probably the opening for the tube. If it doesn't align to the opening it won't seal correctly and you'll have fumes