Are 74, 75 & 76 DT Tanks Interchangable??

[Bill13205]

I'm coming to the conclusion that 74, 75, & 76 Yamaha DT fuel tanks (175 in particular) are NOT interchangeable. Can someone confirm this???

I just picked up a beuatiful 76 DT 175 with a pristine tank. When I started to go thru the bike I found that the tank does not fit propery. (What gives?) I measured the bike from the center of the front tank mount to the center of the rear tank mount. 16.5 inches. Next I measured the tank itself from the center of the front mounting ears to the center of the rear mounting hole. 17.75 inches, hmm. Something is amiss. The former owner admitted that the tank was replaced just before she purchased it.

If I could trouble you all to indulge me, and please measure your 74, 75 or 76 DT fuel tank from the centerline of the forward mounting ears to the centerline of the rear mounting hole. Mine measures 17.75 inches. Mine is could be a 75, based on the locking flip-up fuel cap. I'm not positive. What does yours measure??