A. On the left is the 1310 transmission slip-yoke usually found on OE applications. The yoke on the right is the larger 1350 yoke. Both are available in 27-32 spline count. Start thinking about the larger yoke when approaching 500 engine horsepower, but there are cases where you can get away with more. Be sure to know everything about your power and vehicle weight when you call to order the stuff.