Replacing wiper motor issues / gas tank install

[brodon]

I'm wanting to replace my wiper motor while the cab is stripped down. Every replacement motor has 3 or 4 vertical tabs. Mine has 3 on top and 2 lower. Can't seem to find any parts stores with this motor.

Also; took the inside fuel tank out of my 71 and putting it in my rehabbed 67 cab, but the mounting holes do not line up. Is it possible that there was a different installation during these four years?

Thanks

Don