Driving an underpowered Jeep on the trail or down the road is something that people have been doing since the first army prototypes were tested. Even though V-8 power was made an option for some Jeeps in the early '70s, there are still plenty of underpowered wheezers out on the road today. Even Jeep's latest version of those first military Jeeps, the TJ, has been determined by some to be gutless enough to need a V-8 engine under the hood. This is especially true if your TJ is equipped with the 2.5L four-cylinder. If your base-model four-banger TJ needs more fire under the tires, or your 4.0L fuel-injected six can't muster up the strength to run the dunes, a V-8 swap may be just the ticket for you. Sounds complicated and expensive, huh? Well, don't worry--there are plenty of people who have walked the line in search of more Jeep power, and they've done it all, despite the difficulties of modern emission controls, for a lot less money than it takes to make a Dodge Durango as capable off-road as an almost stock Wrangler. We recently got the opportunity to follow along as the Jeep V-8 conversion experts at Advance Adapters converted a '97 2.5L TJ into a fire-breathing Chrysler 5.2L V-8-powered beast. Here are some of the details, a few tips and, of course, some helpful tricks.
Getting Started
To start out, you've got to have a Jeep in need of a V-8, and the Jeep we had was in serious need of more power. The factory 2.5L was just barely able to spin 35-inch Mickey Thompson tires. A TJ is a good candidate for a V-8 because of its super-sturdy boxed frame, multi-linked coil suspension, and plenty of room under that round, bulging hood. Knowing a V-8 was in order, there was still lots of research to be done and many things to be considered before any wrenches were turned. Our TJ is a California car, so emissions mandated that we find a '97-or-newer V-8 donor vehicle. The people at Advance Adapters decided to use a DaimlerChrysler-based V-8 for a few reasons. One: The wiring between Dodge and Jeep V-8s is similar to our Wrangler. Two: The bolt pattern and spline count on the back of a Dodge or Jeep manual or automatic transmission behind a 5.2L or 5.9L matches up to a NV231J or, in our case, a 4.3:1 Atlas II that had been previously swapped in.
The last stipulation was that the owner of the Jeep wanted a manual transmission behind his V-8, and Grand Cherokees with a V-8 and a manual transmission are rare, if not non-existent. The search began for a '97-or-newer wrecked, preferably hit from behind, manual-transmissioned 4x4 Dodge Dakota, Durango or 1500-3500 truck with a 5.2L or a 5.9L V-8. What we found was an '01 Dodge 1500 4x4 with an NV3500 transmission.