What are the difference between a first gen short bed fuel tank and a long bed of the same (first) generation? (1 Viewer)

[caladin]

What are the difference between a first gen short bed fuel tank and a long bed of the same (First) generation?

I've heard a 2nd gen long be tank will fit, with a little hammering, I might be able to get a new 1st gen long bed tank,
I was wondering what the differences are.

Thanks,