Bringing Up the Rear

 
     

The quick-change rear axle allows quickly adjusting the final drive ratio for street truck performance or for the Bonneville Salt Flats on Project Sidewinder.

Because of the several uses (street, drag race, pulling contests and speed trials) of the Project Sidewinder Dakota, two rear axle housings are used. For the highway and drag race applications, a Ford 9" axle housing are used. The third member can be changed easily for varying rear axle ratio needs. The Dakota bed is configured to allow the use of street tires or drag slicks for this dual purpose. For Bonneville a large quickchange rear axle assembly was used featuring a Dana 60 ring and pinion gear set. This quickchange assembly provides the necessary strength to harness the power of the Project Sidewinder engine and allows very quick gear ratio changes to fine-tune the final drive for Bonneville runs.

 

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An assortment of spur gear sets is used to vary final drive ratios for Bonneville in the Project Sidewinder Dakota.

Quickchange assembly spur gears.

 

Massive Wilwood stock car racing rear brakes are used to stop the Project Sidewinder on the street and from its high-speed runs at Bonneville.

The rear brakes and hubs must be massive to withstand the torque loads and speeds of the Sidewinder Dakota. The parts used are from stock car racing applications where high speeds and tremendous loads are routine.

 

The large Quality Machine quick-change rearend is capable of handling the 1200+ lb.-ft. of torque from the modified Cummins turbo-diesel. The rear high-performance coil-over suspension controls either a Track 9 or a quick-change rear axle assembly.

The Quality Machine quick-change is the key to gearing the low-revving Cummins diesel for 200+ MPH speeds.

 

The cover of the quick-change rearend features a lubricant pump that can be used to circulate the oil through a cooler. The rearend holds four quarts of lubricant.

Quickchange housing rear cover.

 

The Speedway Engineering Track 9 rear axle assembly readily accepts Ford center sections to vary gear ratios for the drags, street driving, or road courses with the Project Sidewinder diesel sport truck.

Track 9 Grand National housing with Grand National hubs & axles uses a Ford-type center section. These hubs interchange with the quickchange axle housing. The Track 9 housing is not a standard Ford copy; it is designed for high horsepower racing use such as NASCAR Winston Cup, Busch Grand National and truck divisions and many road race and speed trial events.

To meet the myriad of objectives for Project Sidewinder, two different rear axle assemblies are used. For the street, drag racing, and road course time trials, a special 9-inch rear axle is used with a variety of ring-and-pinion ratios to suit each event. To achieve the desired final drive ratio for the Bonneville Land Speed Record runs, a quick-change rear axle assembly was used.

Street, Drags, and Road Courses

Handling both the weight of Project Sidewinder and the incredible torque output of the modified Cummins® turbo-diesel engine requires a rugged rear axle assembly. To fulfill this need for street, drag race, and road course time trails, a Speedway Engineering® Track 9™ Grand National housing with Grand National hubs and axles are used. Although the Track 9 accepts the Ford 9-inch center section, it is not a copy of the Ford housing. The Track 9 housing is designed for high-horsepower racing use, such as NASCAR Winston Cup, Busch Grand National, and the Craftsman Truck Series.

One of the advantages of using the strong Track 9 rear axle assembly is that a wide variety of ring-and-pinion ratios are readily available for the Ford 9-inch center section. This will permits selecting ideal ratios for each of the Sidewinder’s intended uses, except one. Unfortunately, given an engine power peak at 3235 RPM and a tire circumference at speed of 92.75 inches, a rear axle ratio of approximately 1.85:1 is required for the Sidewinder to reach the target speed of 210 MPH at Bonneville, even with the 0.73:1 sixth gear overdrive ratio of the New Venture® transmission. Such a low ratio ring-and-pinion set is not available for the Ford 9-inch center section. To solve that special need, something else was required.

Bonneville

The most practical method of solving the final drive ratio problem is to use a quick-change rear axle assembly. For Bonneville, a Quality Machine® quick-change assembly is used with a 3.07:1 ratio Dana® 60 ring-and-pinion. Then by selecting a quick-change spur gear set of 39-to-24 teeth, the final drive ratio is reduced to 1.89:1, which is very close to the desired ratio. The advantage of this arrangement is that the spur gears can be simply and quickly changed to fine tune the final drive ratio at Bonneville to match the power band of the engine or to adjust for tire slippage.

Other

After receiving both the Speedway Engineering Track 9 Grand National and the Quality Machine quick-change rear axle assemblies, Sheldon Tackett fitted both units with identical brackets to attach the Wilwood® disc brake assemblies, four-link suspension, coil-over springs/shocks, the rear anti-roll bar, and the Watts linkage. Red Line® synthetic gear oil is used in both rearends. Connecting the transmission to the rear axle assembly is a 4-inch diameter aluminum driveshaft from Inland Empire Driveshafts®. Wall thickness of this driveshaft is .250-inch.