[JWL]

I think 40 Deluxe came close to asking the same question I have---The stock Ford u-joint is of a floating cross design to allow the driveshaft to misalign without binding. Binding would occur even when the proper pivot locations are maintained if there is spring travel. The front to rear "float" will not resolve this problem because the fixed shaft locations can become higher or lower in relation to each other. In a race car, with very minimal rear end vertical movement, it might not be a serious situation? But in a street car, with normal rearend vertical movement, it seems like something has to bend, bind, or break if the u-joint does not self-center.