We suppose back when gas was under a buck a gallon nobody really gave a damn about mileage, but today, paying over $60 to fill your tank just hurts too much to ignore. Given this economic incentive, it’s no wonder so many gearheads with TH350, TH400, and other non-overdrive transmissions are looking for a solution to drop their rpm on the highway. Yeah, they could pop in a set of uber-high gears, but then their off-the-line acceleration would take a buzz-killing hit. We’re Americans, and we want our cake and a big freaking fork to eat it with!
Well, prepare to chow down since it’s easy to get better mileage on the highway and still retain your neck-snapping acceleration off the line. Yep, today’s lineup of overdrive transmissions makes ditching that dinosaur under your trans tunnel a snap. But what if you want a little more? What if your left foot and right hand are complaining of boredom when cruising about, or even more so while blasting through a driving event? Then what you need is a manual transmission with an overdrive, and arguably the best one out there is Tremec’s T56 Magnum. It offers the grin-plastering fun of shifting along with two full gears worth of overdrive goodness.
Internally, the Magnum is pretty much the same as what’s found in the fifth-gen SS Camaro’s TR6060 six-speed. There are triple-cone syncros on the first four gears for smoothness, and it can effectively handle over 700 lb-ft of torque. The aftermarket version of the TR6060 was designed to be swap-friendly. It has a separate bellhousing, dual speedo pick-ups to accommodate both electric and mechanical gauges, and it can handle both hydraulic and mechanical clutch systems. Of course, there’s still the matter of getting this 21st century piece of technology under your vintage Camaro, but thanks to Hurst Driveline Conversions (HDC) it’s a lot easier than it used to be.
HDC offers a basic Magnum swap kit starting at $2,995, but we opted for their Elite kit ($4,295), which is more geared towards doing an old-school automatic to high-tech manual swap. To this we added some clutch hydraulics ($595), upgraded the bellhousing ($330) along with the clutch ($100), and tossed in one of their billet Blackjack shifters ($295). That totaled up to just over $5,600. It's not cheap, but it’s a great value for what you get.
For a car, we chose Doug Renner’s ’69 Camaro. Doug’s ride does pretty well on the autocross even with a peg-leg rear and TH350 trans, but he just knew that his outdated drivertain was holding back his awesome driving talent. Besides, cruising the highways at speed was giving his wallet a real beat down. So we gathered up our parts, stuffed them in Renner’s low-slung Camaro, and headed over the Brett Campbell’s shop, Campbell Customs, to see what’s involved in the transformation.