I chatted with places like Summit and Jegs - they don't know their butts from a hole in the ground and could answer anything about the Ford steering boxes shaft size and spline. I did have a 3/4" - 36 spline steering coupler laying around and went down to Autozone and had them pull a box off the shelf. But it didn't fit - it was close, the box is just a touch bigger and couldn't tell if the spline count was. I have checked out some websites about steering u-joints, but there really was no Ford products in regards to pickups and vans. Plenty of Mustang though.