A '93 LT1 Wrangler Project Resurfaces
Some of you may remember the LT1 Wrangler project we did back in 1993. For those of you who don't, we enlisted the help of Chevrolet and installed an LT1 V-8 and a 4L60 automatic in a YJ Wrangler, running the buildup in a series of features. John Currie was in the middle of building an almost identical vehicle of his own, and he helped out tremendously on this project.
Both Jeeps ran well, especially since Mark McPhail from the GM Motorsports Technical Group came to California and ensured that everything was up to par. So imagine our surprise when neither Jeep would pass smog, even though they both put out less than 1/10 of the allowed emissions. To make a long story short, the California Air Resources Board (CARB) had a number of rules that precluded the use of LT1 motors in our Jeeps. Left with few alternatives, both John and I eventually sold our Jeeps to out-of-state buyers.
Last year, we were perusing Truck Trader online and were surprised to see John's blue LT1 YJ for sale. After some negotiating, we purchased it and brought it to Utah, where it could be legally owned and operated. It had been more than a decade, but the YJ hadn't changed a bit. Other than the tires, which the owner had swapped out at some point, everything was exactly the way it'd been in 1993. Apparently, the owner had bought it from John, parked it in his driveway, and then let it sit. He finally just got tired of it constantly being in the way.
This YJ is a window to the past, showing us exactly how we used to build Jeeps for hard-core trail use. Along with the LT1 and the 4L60 (the "E" didn't arrive until the following year), John had installed a Dana 300 with a twin-stick shifter. Tom Wood (then of Six States) built the driveshafts, which connect to the 57-inch-wide Ford 9-inch front and rear ends. Outers from an '86 CJ were used up front, Currie disc brakes were used in back, and both axles sported Detroit Lockers and 4.56 gears. While a flat crossmember would have worked just as well back then as it does today, this YJ doesn't have one. To mount the 300, John actually built a nice little skidplate below the factory crossmember. It hung down too far back then and still does today.
So, after all these years, how did the old YJ run? To sum it up in one word, badly. It chugged and missed and overheated. Since it hadn't chugged, missed, or overheated before it went into hibernation, we figured it could be fixed. The LT1 was the first Chevrolet V-8 where engineers experimented with distributor placement and design. As it turned out, the Optispark distributor wasn't really one of their better ideas. Sitting under the water pump, it could get wet and corrode inside, causing all kinds of havoc. After removing the Optispark, which was a pain, and disassembling it, it turned out that this one was completely corroded inside. We replaced it with a brand-new one from Street & Performance, and - voila! - the chugging was gone and the LT1 ran well again.