More power, more performance, and more economy. That's what we all want for our 4x4s, but it isn't easy to reach these goals without spending a bunch of bucks. However, the three basic bolt-on items that almost always help to free up some ponies are a better air cleaner, hotter spark, and free-flowing exhaust. Since an engine is basically an air pump, letting more air in, igniting all of the fuel, and helping all of the exhaust to get out quickly usually makes for more power, performance, and economy.
Our '79 Jeep Cherokee got the spark and air filter issues addressed in "Power Tune" (May '01), and we were amazed at how much better the beast ran. In fact, our next step was to slap some headers on it to make the rig really run right, but we got into some "emissions-legal" issues, like the local smog laws. It so happens that in Arizona and California (our only registration choices), the federally mandated factory equipment needs to be in place and functioning, or have a smog-certified replacement part installed. However, we couldn't find a single company that had CARB (California Air Resources Board) approved headers, so we were stuck.
Moving to another state or country, or only using the Cherokee off road, seemed a bit excessive, so we delved further. We found that Edelbrock offers a Tubular Exhaust System (T.E.S.), including headers, that is certified for this powertrain, but for '81-'91 models. The differences we knew of between a '79 and later was that the auto tranny was a TH400 and a Quadratrac transfer case in the '79, and a 727 TorqueFlite and NP208 in the '80 and later. Except for the fact that the front driveshaft is on the driver side on the '80 and the passenger side on the '79, they are virtually the same rig. After scoping out the T.E.S. we figured we could get them to fit and pass through the smog check station in just about any state.
We trundled down to Performance Products in Van Nuys, California, to try and make our mess work out right. We first met up with this company on our Ultimate Adventure (Oct. '01) where they were the title sponsor of the trip. After seeing the amount of stuff they carry and the super-sano installation bays, we knew they could handle the project. Here's what we came up with to get some somewhat smog-legal headers for our own rig to keep the smog police at bay.
01. Our Edelbrock T.E.S. headers came plain, even though they are available coated. We sent our set off to Jet-Hot coating for the most durable finish available. The coating keeps the headers cooler, makes more power, and allows for lower underhood temperatures. | 
02. Edelbrock PN 6881 is specified for an '80-and-later Wagoneer and has the all-important CARB number stamped on a welded tag on the tube. This is what gets you past the smog police, along with the associated engine compartment decal. |
03. Our first step was filling the bay at Performance Products with our '79 Cherokee. The stock exhaust has a crossover pipe that loops under the front driveshaft and often hits. Top-technician Alfredo broke out a Sawzall and removed the old pipes in a snap. | 
04. After the encrusted old manifolds were wrenched off the engine, the air-check valve for the air-pump system is removed. The valve screws right on to the new T.E.S., and the new headers slip back onto the engine. |
05. The bolts supplied with the new tubes were a bit long, with some interference between tube and flange. After a quick trip to the grinding wheel, the bolts slipped right in. Our problems began when we saw the left collector dumping right into the Milodon oil pan. The new pan interferes with the collector, while the stock pan would clear fine. Instead of just hooking up the Edelbrock crossover pipes for a bolt-in installation, we were stuck. | 
06. Performance Products works closely with Luna's Performance Exhaust, located around the corner, so they suggested we get some custom mods. Manager Dan Luna took one look at the mess and said, "No problem," and proceeded to whack off more old pipe for a better installation. |
07. To keep the good sealing properties of the donut-style connector, Luna cut the collector halfway through, then heated and bent the end into shape. This was the only way out of our predicament, short of changing the oil pan to stock or going back to stock exhaust manifolds. Luna precisely formed the end into its new location, then welded it back together. | 
08. Luna has been in the biz for more than 15 years and loves to do the difficult jobs on rods and 4x4s. We showed him our concerns for axle-to-exhaust clearance, and he started bending tube faster than we could snap photos. The passenger-side header uses a flat flange to a donut-type connector and required no mods. |
09. By simply routing the exhaust around the front of the pan, we gained tons of clearance for the front axle and driveline. Luna grafted the left tube into the right side just like the stock and Edelbrock system, so we doubt our mods will hurt performance. In fact, we could even hear ourselves talk after the job, and the Cherokee felt a lot spunkier. | |