Fuel tank differences?

[Jeff Gordon]

Thanks Keith,
I had a closer look today and out of 7 tanks I have here only 2 are different.
5 of them are what you described as Ford have flat senders and 6 screws.
2 of them assumable Chevy have a higher odd shaped sender held in with 5 screws.
I also noticed that the seam that runs the length of the tank is different at the ends.
The Ford ones are squashed at the ends and spot welded down.
The Chev ones run square to the end.
BTW the Chevy ones are off my C15A and the Ford ones are on a C15 and Cab12 Fords.