1979 Suzuki GS 750 Tank is not as described. Help Identify?

[Bradlab2k]

So I bough this tank off of eBay and it was described as a 1979 Suzuki GS 750 Tank (Supposed to fit 77-81). Well, it didn't fit my 79 GS 750E. Now I am trying to find a way to identify what it actually fits on. If anyone can help identify it, I'd really appreciate it. I have some pics and measurements for it that I've attached.

http://s206.photobucket.com/user/bradlab/library/GS%20750%20Tank%20unable%20to%20identify

[TeamDar]

It looks like a 1977 GS750 tank. It should fit unless it is a GS550 tank?

[steve murdoch]

Looks like a '77 to me.

[78gs750e]

looks just like my 78 gs 750e tank.

[BigD_83]

There is no shortage of images of 550s with the same paint scheme. Did any of the 550s have the fuel door over the cap like the OP's tank?

EDIT- Ok. I looked and found images of red 550s with the fuel door

[BigD_83]

From the ghost in the machine via email:

"The 550 tanks look almost identical to the 750 tanks but are about 2-3" shorter due to the smaller engine cradle in the 550 frames. Yes, I have a 550 tank also."