Rapid Response recommends the Dynotech 3.5" X .065" X 1350 X XXXX Driveshafts for the USAR Pro Cup application because of the high RPM and resulting Critical Speed issues.
Switching from the 1310 series U-joint to the more common 1350 series u-joint requires replacing the existing 1310 End Yoke with Rapid Response's Spicer 1350 End Yoke for the Quick-Change Rear End.
If you are ordering a 3.5" X 1350 shaft to replace a 1310 shaft, please refer to this chart to determine the correct length to order.
Spec #1 is the measurement from the end of the Tailshaft housing to the center line of the 1350 Quick Change End Yoke.

| If SPEC #1 = | Order C/L TO C/L |
| 45.75" | 42.5" |
| 46" | 42.75" |
| 46.25" | 43.0" |
| 46.5" | 43.25" |
| 46.75" | 43.5" |
| 47" | 43.75" |
| 47.25" | 44.0" |
| 47.5" | 44.25" |
| 47.75" | 44.5" |
| 48" | 44.75" |
| 48.25" | 45.0" |
| 48.5" | 45.25" |
| 48.75" | 45.5" |