After yanking the interior, one of the first things to go in almost every GM metric bodied car being turned into a race car is the rearend. That's because stock GM rearends use a C-clip to retain the axles. So, if either the C-clip or an axle breaks, you not only wind up with a broken axle but you can also wind up with a missing rear wheel and your car backed into a wall.
One option is to install a C-clip eliminator kit, but you still won't have the benefits that come from racing a Ford-style 9-inch full floater rearend. Plus, by the time you've rebuilt the stock rearend to proper racing specs it often makes better financial sense to use a new aftermarket rear anyway. That's why most Street Stock racing classes allow a full floater 9-inch rearend--the safety and economic benefits are just too great.
Quick Performance (QP) offers a wide range of gearing and rearend options for all types of racers. Its line of 9-inch full floater rears includes mounting options so that they will bolt right up to GM "metric" chassis like the mid-'80s era Monte Carlos and Regals. Quick Performance has put together complete rearend kits designed specifically around the needs (and the rule books) of Street Stock racers, so we decided to try one out for a car being built by racer Jason Gulledge. The kit we ordered up includes absolutely everything needed except for the gear oil of our choice, bearing grease (if you choose to use it) and silicone or a gasket for sealing the center section to the housing.
Possibly the best part of the deal is QP can build the center section for you to the specs you require including the gear ratio you need. We spec'ed a 583 gear ratio with a spool for racing on a half-mile track with long straights and tight turns. Being able to order up a complete center section built ready-to-race with the correct backlash and gear mesh eliminates one of the biggest hassles when it comes to building a new rearend. The rest of the build can be handled by just about anyone in their shop with standard handtools.
Besides the center section, we were also very interested in checking out Quick Performance's new Extreme Floated axle housing that uses a new "banjo" section of the housing that, according to Quick Performance, has been redesigned to be both stronger and lighter. QP claims that the new Extreme housing design chops 9 pounds of unsprung weight off the rear versus a standard G-body floater rearend. We also wanted to get a look at QP's new adjustable lower brackets which allow you to adjust the height of the lower control arm mounting points. Just like the adjustable bars on a Late Model, adjusting the height can help control how the car handles as the track changes. The adjustable brackets work with stock stamped steel G-body suspension components, so they should be legal at most tracks.
When using the adjustable lower brackets, QP recommends running the left-side lower control arm in the bottom hole and the right side in the second or third hole down (there are five holes total). If the track gets dry slick, dropping the right-side bar down a hole or two will help tighten the car back up, and doing the opposite will help the rearend turn more when the track is tacky and hooked up.
Although the Quick Performance Extreme Floater rearend kit can be assembled by practically anyone, we had gear specialist Gary Medlin of G.M. Racing give us a hand on the assembly--and his expert opinion in the process. And while we went with the complete kit, if you already have some of the components you need, like brake calipers and rotors for example, QP can put together just the parts you require.
We were also surprised by how affordable QP makes installing a new rearend in your car. For example, the full floater housing set up for a G-body, or Metric chassis, sells for just $950. That includes a new housing, axles, hubs, bearings, studs, and quality Wilwood rotors. For $30 more, you can have the adjustable lower brackets added. Brake calipers complete with pads and all the brackets required for installation can be had for $100, and finally, assembled center sections with a mini-spool start at a manageable $399. Now follow along as Gary gets to work.
