vf500 and vf750 gas tank interchangability?

Hey guys, possible newbie question here (well definite newbie question) my current vf500 project bike didn't come with a gas tank, getting one for sub $200+shipping is near impossible but there is a vf750 at a local salvage yard with petcock and very little rust for $90. So my question is will the tanks interchange? I've looked through a few threads and it seems like the 500 is slightly smaller than the 750 (frame wise) but I never just like to assume.

Thanks

 

Two different animals, best bet is to watch E-bay for a bit and you will find a peach in time or buy a complete bike that is in good shape that does not run. Winter is your best friend right now.

 

It would help if you gave the year and color of the bike as you never know who is lurking here with the loot you are looking for.