When ordering universal joints, these are the dimensions you will need. "E" is yoke saddle length from bearing cap end to bearing cap end. "D" is bearing cap outside diameter. "A" is from bearing cap to bearing cap. The basic Spicer number will be 1260, 1310, 1330, or 1350. In Mustang V-8 applications, 1310 is most common. Big-blocks use 1330. If you're racing, get the 1350.