Anybody know what length driveshaft I need?

LXguy said
Shaft appears to be 52.5" from the center of the u joints.

My yoke measures 3.25" across? What U-joint would that be?

EDIT: A Ford 1310 Fits perfectly.

you need to check which one you have , I think the ford 1310 is close to the 7290 .

measure the inside to inside distance between the caps .