The '94 YJ Wrangler we found languishing in pools of its own fluids was immediately sent over to Craig Ross at Rockworx in Montrose, Colorado, so he and the rest of the Rockworx crew could work their magic on it. Dynatrac built the ProRock 60 front and rearends you read about earlier this year.
The Dynatrac ProRock 60s can handle plenty of power. All we needed now was a powerplant, transmission, and transfer case to get that power to them. Advance Adapters has been our partner in countless project vehicles, so we once again turned to the company for help. Advance Adapters offers brand-new, completely assembled Gen III Vortec V-8s, and, of course, the Atlas transfer case that's a "must-have" upgrade for us.
1. Advance Adapters offers brand-new GM Gen III Vortec V-8s. We chose the 5.3L that's available in Chevrolet and GMC pickups and sport utes. The new Gen III V-8s are more powerful and efficient than ever. Cooling efficiency has also been greatly improved.
It's hard to fault GM V-8s. For decades, they've been the benchmark that all others strive to emulate. The new Gen III Vortec V-8s are more powerful and more efficient than ever. Cooling efficiency has been greatly improved, which helps those of us who plan on using our vehicles in very hot climates, sometimes idling around in the rocks all day long. While these are the same V-8s that are currently installed in GM pickups and sport utes, they can also be adapted to run in Jeeps or other trucks easily with the help of Advance Adapters' products.
Advance Adapters also supplied one of its Rad-A-Kool aluminum radiators and Spal fan kit. The crossflow Rad-A-Kool utilizes 1-inch-wide core tubes and is completely TIG welded. It's a bolt-in unit and came configured to work with our 5.3 Gen III V-8. The super-strong Atlas transfer case needs no introduction. We chose one with a 3.8:1 Low range. The Atlas allows the use of 2WD High, 4WD High, 2WD Low, 4WD Low, and front-wheel drive. Front-wheel drive allows us to turn a lot sharper in tight places off-road.
We procured our wiring harness and computer from Howell Engine Developments. The company has been around for years, offering quality harnesses and fuel-injection systems for off-roaders and hot rodders. We've utilized Howell harnesses in every swap we've done and have never had a problem. Howell sent a GM computer and harness that work with all factory sensors so our 5.3 runs the way the engineers intended.
2. The Advance Adapters Gen III Vortec V-8s arrive completely assembled and ready to install. While we didn't order our 5.3 with it, air conditioning is also available.
Since our 5.3 V-8 was going to be working just as the factory designed it, we wanted the transmission to work that way too. We called Toy Shop Transmissions in Pomona, California, and ordered one of its famous, heavy-duty 4L60E automatic overdrive trannys. The Toy Shop is famous for its transmissions, especially in the hot rod and street rod world as well as on the Bonneville Salt Flats, where Toy Shop transmission-equipped vehicles have raced across the salt chasing land speed records.
The 4L60E is an electronically controlled version of the venerable 700R4. With the Howell harness and computer controlling it, it works just as the factory intended it to. The Toy Shop adds heavy-duty front and rear sprag assemblies and shell. The shop replaces the aluminum pistons with steel ones in the input housing. Pump mods include polishing the inside of the pump and the installation of a 13-vane pump rotor. The valve body is modified to increase clutch application pressure and lock the converter sooner and stronger. Oil flow is also increased to the cooler. A heavy-duty, 1,700-rpm stall torque converter with larger bearings and furnace-brazed fins was also installed. We can't afford to have transmission failures off-road (or, for that matter, on-road). The Toy Shop 4L60E will ensure trouble-free operation, no matter where we're operating.
Our Rockworx YJ project is coming together with top-quality components. The Rockworx staff's expertise continues to amaze us as they perform this buildup. Not only do they know the technical side of building vehicles, but Craig and the gang are hard-core off-roaders who know what's needed in the dirt or rocks.
3. Wiring an engine swap can be difficult, especially with today's computer-controlled mills. Howell Engine Developments make this easy with its harnesses and GM computers. All the factory sensors are used so the V-8 should run as designed at any altitude or attitude. The Howell harnesses use OE-quality connectors and wiring. | 
4. Craig bolted the 4L60E automatic overdrive transmission from Toy Shop Transmissions to the 5.3. The Toy Shop 4L60E is heavy-duty with modifications that allow it to stand up to the abuse we plan to dish out off-road. | 
5. A&B The superb geardriven Atlas transfer case from Advance Adapters can be configured many ways... |
...We chose a 3.8 Low range and lefthand drop. The Atlas can be rotated so it sits flat under the vehicle for more ground clearance. | 
6. Rockworx was able to get our Atlas almost flat. You can see here that our Wrangler is going to have a flat crossmember. | 
7. Once the power gets to the Dynatrac ProRock 60s, we need to get it to the ground. A set of 37x12.50R17LT BFGoodrich Red Label Krawler radials mounted on 17x9-inch Mickey Thompson Classic II alloy wheels with OMF beadlocks will do the trick. |