1969 Road Runner Project, Part VIII

The Holley Project Road Runner

At the 1999 Performance Racing Industry show held in Indianapolis, Indiana, we were on a mission. Having just recently observed the dyno results of the Indy Cylinder Head-built 542ci Wedge, we immediately recognized the need for a rearend assembly that would offer the strength needed to shelve our concerns for street reliability as well as occasional wheel-lifting launches.

Initially, we believed that a well-built 8¾ would easily meet our needs, but that was not the opinion of Jay Prosch-Jensen of Drive Train Specialists’ Custom Services division. Jay said, “With the limited availability of seasoned 8¾ housings, we really would rather see you with a DTS Dana 60.”

With the 542ci big-block already planned for back-up by a Herb McCandless-built A833 four-speed (“4-Speed Clinic,” page 36, Mopar Muscle, June 2000), the thought of yet another assembly of Hemi legend made sense for the Holley Project Roadrunner. But this would not be a rebuilt Dana 60. “DTS Dana 60s are manufactured from 100 percent new components,” said Prosch-Jensen. “Starting with new Dana 60 castings, a print is drawn to determine the length and pinion offset of the housing. Then a pair of 3-inch I.D. axle tubes are cut and turned in the lathe for a press fit. The rearend is installed in a jig to assure proper alignment during the process of welding the axle tubes to the center section.”

Additionally, Jay and the crew at DTS Custom Services are quite familiar with the Mopars. Full service includes welding of suspension mounts in the proper location for specific applications.

Because of the multi-use characteristics of the car, we wanted the driveability of Sure Grip with the drag race reliability of a locker. With that in mind, Jay recommended the use of an ARB air operated locking differential. The Australian-built Air Locker—with a flip of a switch—converts from an open rearend to a spool. With the accompanying air compressor, you simply air up when you want to lock the differential.

1. The DTS Dana 60 is constructed using only new components, at the center of which is an all new Dana 60 centersection. This rearend is a custom assembly and can be ordered in any width with any currently available ring and pinion ratio starting at 3.54 and up to 7.17:1.	2. DTS, in addition to building custom rearend assemblies in both their Wayland and Warren, Michigan, locations, offers full-service installation as illustrated here.	3. Axle tubes are custom length, 3-inch I.D. cut individually from DTS' tubing stock.
4. In-house assembly helps DTS maintain tight tolerances and customer satisfaction. On the lathe, each centersection end of the axle tube is machined for a precise fit.	5. Here are the components prior to welding the axle tubes to the centersection: the new Dana 60 center, axle tubes, spring perches, and one end flange for mounting the brake assembly. DTS can build your Dana 60 to accommodate factory or aftermarket brake systems, like our soon-to-be-installed system from Baer Racing on the Holley Roadrunner.	6. In order to guarantee correct fitment of the differential, DTS uses this gauge fixture to measure pinion centerline.
7. DTS used 35-spline axles for our assembly. Each axle carries a 10-year warranty against breakage for a full replacement.	8. This detail photo of the installed ARB Air Locker shows how compressed air is delivered to the Air Locker. Aired up, the Air Locker operates in a "locked-up" mode (like a spool). When air is released with the switch, the unit operates as an open rearend.	9. DTS' Dana 60 girdled cover offers extra strength, access for lubricant service, and better cooling as aluminum transfers heat far better than a steel cover. Billet aluminum caps assure alignment under the load of the Indy Cylinder Head-built 542ci engine, which in our testing produced over 700 lb/ft of torque at the flywheel.
10. Our complete assembly as shipped to Muscle Car Restorations in Chippewa Falls, Wisconsin...	...for installation in the Holley Project Road Runner.	11. The axles carry a 1350 series forged yoke--that's even larger than the Mopar Dana 60 7290 Mopar. Additionally, the axle tubes and axles that DTS installs offer a larger tapered Timkin wheel bearing. This setup outperforms the revered Mopar "Green" bearings and requires no end-play adjustment. This setup requires the use of aftermarket brakes.