Mark Williams Enterprises sells ring and pinion kits for just about every model rear end. Per our application, we went with an 8260 alloy specifically designs for our high-shock application. Simply, high-shock is referring to the process of dumping the clutch, and accelerating the car to the 60-ft mark in less than 1.4 seconds. Also, Mark Williams' aluminum spool is hard-coat anodized for durability and it is half of the weight of its steel counterpart.
It's always good to have a stack of rear end shims laying around when performing this installation. We actually did this laying down on the floor of Robert's garage with a set of jackstands. If you have access to a lift, it makes life that much easier and will ultimately lower your chiropractor bills.
We set the entire spool and ring gear in place using the same shims that came out. This is a great starting point as often, you will use the same shims to make the switch. Getting the assembly in place is a little tricky, as it has to go in completely straight. If it is slightly off kilter, pull it back out and start over again. The last thing you want to do it damage the aluminum spool.
We then torqued the main caps into place and broke out the gauges once again to check the lash between the ring-and-pinion. Optimally, we are looking for approximately 7 to 8 thousandths of an inch. It actually took us three tries to get the correct shims in. We had just about every shim size from .001 to .040 and it saved us a great deal of time and effort.
At this point, we can reinstall the driveshaft with the two U-bolts and also install the rearend cover. Use both a gasket and a bead of silicon to ensure that you don't have a leakage problem down the road. Also, tighten the rearend cover bolts in a pattern that never has you tightening two bolts right next to each other. Bounce around and make sure that all the bolts are tightened fully.
We filled the rear with two quarts of Joe Gibbs Driven qualifying rear fluid. Designed specifically for race cars, Joe Gibbs Driven goes to great lengths to ensure its product is both safe and horsepower-friendly. Using a lighter weight rear fluid can improve performance, but the wrong weight can cause the ring-and-pinion to seize. Make sure you talk to a company representative before choosing.
At this point, we can slap the brakes back on and head to the track. As always, take your time when installing a ring-and-pinion set and make sure to take accurate measurements along the way. Not doing so can creep up to hurt you later when you are in a final round match up. Plus, no one wants to be stuck on the starting line with a broken rear. People tend to laugh.