How to re-index 620 torsion bars
Raise the truck off of the ground and set it on jack stands. The front wheels should be hanging freely with no weight on them.
In front of the middle crossmember, you pull the boot forward to reveal the lock ring. Work a thin screwdriver into the edge of the ring. It will be tight. I had to work the angle back and forth while occasionally tapping the back of the handle with a hammer. Once you get under the ring, work it out slightly. Do not pull the screwdriver away or the ring will pop back in place. After you have worked it off part way, grab the snap ring with some needle nose pliers.  Pull the ring off the rest of the way. Be sure to still keep the screwdriver under the lock ring while removing it with the pliers.
  1. Pull back boot
  2. Pry on edge of ring
  3. Snap Ring Removed
  4. Pliers on ring
Unscrew the longer adjuster bolts and completely remove them. Tap the rear arm of that holds the adjuster bolt out of the crossmember. Hang onto the torsion bar. It can slide out at either end. Feel the splines in the end of the bar as you turn the adjuster bracket. Only move it one notch and then slide the bracket back onto the torsion bar. The reindexed bar is on the right.
To lower the truck you move the left side bracket counter-clockwise and the right side clockwise.
After the bar is reindexed, just hold the lock ring up using pliers and hit the back of the ring with a hammer. It pops on real easy. Put the dust boot back in place. Tighten up the adjusting bolt to about the center. This should lower the truck about 5 inches. Removal of the bump stops is required.

Short Shocks

Ford Pinto front shocks are slightly shorter than Datsun truck shocks and fit the factory mounting location. They allow free travel without bottoming out like factory shock obsorbers do. The Factory Nissan shocks are shown in black compared to blue Pinto shocks.
​Unbolt and remove the front bump stops  from the Datsun when the factory shocks are out. This is required for clearance on a lowered truck. 

​The Pinto shocks come with a metal tube inside of the lower bushing. Remove and discard the tube before installing in your Datsun 620.
KYB Gas-A-Just Shock KG4511 (Pinto)