While the gas crunch that rang in the ’80s can be held responsible for the sub-200 hp “muscle cars” that were jammed down our throats by the Big Three in those days, it also brought us a grip of new technology. At the outset, innovations such as computer controls and electronic fuel injection that were deemed necessary to lessen harmful emissions and increase fuel mileage were unsettling and unwelcome, mostly due to our lack of familiarity with their inner workings. But it wasn’t long before the aftermarket embraced (read “found a way to modify”) this equipment as is evident by their place in today’s hot rods.
Possibly the best piece of new equipment to come out of the ‘80s was the overdrive transmission. And today you’d be hard-pressed to find a hopped up muscle car in any garage or car show without a four-speed automatic, five- or six-speed manual, or an auxiliary overdrive unit. While these babies made their way onto Detroit's assembly lines because of their decreased fuel consumption, we quickly found out that they made our high-performance rides more drivable (and fun to drive). We've heard more than one enthusiast make the claim that an overdrive was “the single biggest performance improvement” he had made to his car. With the advent of overdrive, the disadvantages of adding stiffer rearend gears, a slippery converter, and more camshaft barely enter into the debate. Now you just do it because having the extra gear makes it all easier to live with.
The 700R that was putting the power to the ground in our Crossfire Z was first introduced by Chevrolet in 1982, and would eventually replace the Turbo 350. It offered a new lower 3.06:1 first gear and a 30-percent overdrive fourth gear. The originals did have some inherent problems and were prone to failure, especially when put behind anything with decent horsepower. The best thing that ever happened to these transmissions, renamed in 1990 to 4L60, was the conversion in 1993 to a computer-controlled shifting system. Designated the 4L60E, the electronic trans uses a computer to provide unlimited shift point and pressure adjustability as well as eliminates the often-problematic throttle valve (TV) cable adjustment. With 25-plus years of refinement, and the hard work of aftermarket experts like the folks at Phoenix Transmission, it’s now possible for these transmissions to handle almost 600 hp.
So follow along, and we’ll show you what it takes to upgrade a third-gen with one of Phoenix’s 4L60E’s (PN PT4L60ESS, $2056).