From 76 compared to 90+: The fuel filler neck is different, as is the tank breather setup.
78+ fuel injection tanks have an inbuilt swirl pot.
The 78+ FI tanks had an in-tank fuel pump. There are two different sizes of tank sender / in-tank pump flanges.
Carby tanks are different to FI tanks - carby tanks have internal piping; FI tanks don't, they have a swirl pot and rely on an in-tank pump and return line.
A service bulletin for the pre-78 tanks in the US (all US market cars were FI after YM 72) shows the process to fit the 78 -93 in 1974 140/164 and up to 78 240/260; the same tank was used all the way to YM93.
The 1990+ tank will bolt up to the 76 body without dramas. You need to replace the tank filler piping, the tank breather, and re-route the fuel lines that connect to the main fuel pump (if K-Jet, you'll need to sort out a bracket to mount the original main pump; if carb, you'll need to make sure the in-tank pump doesn't over-pressurise the carb.
