When Project g/28 started out, we were on a tight budget to hit our goals. Given this, the choice of a more wallet-friendly TH350 automatic transmission was the right way to go; it was built to handle all we could throw at it, even at the road course. About the only downside was that driving the car on the freeway with 3.73 gears was about as much fun as a root canal. We had been toying with the idea of installing a manual transmission, but we knew the task would be daunting since we would have to find linkage, a cross-member and all other minutia required to make the swap happen.
Then in a chance encounter with Keisler Engineering, the company mentioned it had developed a complete swap kit for our '76 Camaro and we should give it a try. We no longer had to worry about chasing parts from a dozen companies, hoping they worked together, so the decision was made to pull the trigger and get the kit.
The Keisler kit is optimistically called the "Perfect Fit" kit, but we were a little hesitant to believe the marketing pitch. We have installed enough stuff to know that nothing fits perfectly, but if it were close, we would still be happy campers. After talking with Keisler, we decided to go with the Tremec TKO-600 transmission, which is rated to handle 600 ft-lbs of torque, since it had a gearing ratio that would work better with our setup. The .64 Fifth gear would make cruising the highways a breeze and the 2.87 First gear would work well with our 3.73 rearend gears. They also offer a TKO-500, which is rated to handle 500 ft-lbs of torque due to its more-aggressive First gear ratio of 3.27, for a couple hundred bucks less than the TKO-600. Also, its Fifth gear ratio of .68 is a tad less mileage friendly. Keisler offers these kits for a wide range of cars including GMs, Fords and Mopars. For some applications, they even have kits to swap in T56 six-speeds.
With the plan in motion, we took some measurements of g/28's driveshaft and answered a few questions about the engine currently in the car. (Our 383 was internally balanced, dictating a zero-balance flywheel). With gas prices over three bucks a gallon for the cheap stuff, we were anxious to get started. We also decided this was a great time to stiffen up the Camaro with a set of Global West subframe connectors and replace the worn-out 30-year-old bushings with some solid units.
Two weeks later, the parts showed up on our doorstep and we drove the Camaro over to Don Lee Auto in Cucamonga, Calif., where the owner, Tim Lee, is always happy to lend us a hand, and more importantly, one of his lifts. Check out the photos for the high points of the installation, which took just two days, not including time for the unrelated body bushing and subframe connector installation. This is clearly a job for the advanced mechanic, although the TKO kit has been installed time and again by the DIY guy in his driveway. We do recommend a lift, however.
Prior to the TKO install, gas mileage was firmly mired in the 11 to 12 mpg range. It's not so much that our mild 383 was a gas hog, but that the 3.73 gears and loose converter kept engine rpm in the stratosphere. Rolling along at a glacial 55 mph had the engine cranking 3,000 rpm. We can now cruise at 70 mph with the tach at a more reasonable 2,000 rpm. This huge difference is the result of the engine turning 36 percent fewer revs, and that's assuming the converter was locked to start with (it wasn't). Account for 5 to 10 percent more rpm from converter slippage with the old TH350, and the difference is even higher. We guess you could say we weren't surprised that we got a 33 percent improvement in fuel economy, from 12 mpg to 16 mpg--and that was with a heavy right foot.But there is another dimension to an overdrive transmission. Pistons, rings, guides, valve seats, valvesprings, cylinder bores and bearings all have a finite life expectancy, so an overdrive transmission like the Keisler Perfect Fit TKO can literally add years to the life of an engine. Even without the added fuel economy, a typical hot street engine with a 50,000-mile life-cycle may last another 10K or 15K miles, and that's cash in the bank.
Lastly, the frenetic pitch inside the cockpit has been lowered from "deafening" to a dull roar. We can now hear a cellphone ring, although we're not sure that's a good thing. At least it's now possible to hold a conversation with a passenger without getting a sore throat.
And the performance? With a 2.87:1 First and 3.73 rear cogs, g/28 lays rubber like a champ. Then there's the simple fact that five gears are better than three, because it's easier to keep the engine in its power band when you want it. The mathematics of gear multiplication will have to suffice for now until we get it to the track for some real numbers (the outgoing TH350 had a First gear of 2.52 versus the TKO's 2.87, so you can imagine how much sharper the acceleration is). We're itching to try it out at the road course, but we've got a few more unrelated things to fix first. There is plenty to talk about on the up side, stuff like better fuel economy, longer powertrain durability, lower cabin noise and added performance. If you already have a manual trans in your ride, the cost of the Perfect Fit TKO kit is under $3,000, so it's an easy pill to swallow. If you are converting from an automatic tranny, there are a few more parts needed like a bellhousing, clutch, and pedals. This bumps the price up to $3,995 for mechanical linkage and $4,299 if you want to switch to hydraulics like we did. There simply is no down side to it, unless you don't know how to drive a stick. We'd have to say it's the best money you can spend on your car.
|
The $4,299 kit from Keisler contains just about everything you will need to go from an automatic transmission to the new manual five-speed. This includes the TKO-600 tranny, a lightweight bellhousing (15 lbs.), billet flywheel, driveshaft, hydraulic clutch master, clutch reservoir, appropriate clutch, new pedal assembly, new speedometer gears, mechanical speedometer cable, shift handle, shifter boot, trim ring and all the necessary bolts and fasteners. They also offer a kit ($3,995) that uses mechanical linkage if you prefer, but we felt the hydraulic system is the easy way to go, especially when going from an auto to a manual transmission. If you are already running some sort of manual transmission, like a Muncie four-speed, you only have to shell out $2,995 to have all the benefits of the overdrive Tremec TKO-600. |
In some cases, Keisler modifies the original Tremec to better fit the application. In our case, they offset the shifter to the left so it will be in the right location when we add the new center console. The red arrow points to the plug you would use to get a VSS signal for an electronic speedometer, and the blue arrow points to the spot where you would wire in the neutral safety lockout. Tremec warranties the transmission for 90 days, but Keisler doubles that warranty to 180 days and it doesn't start until installation is complete (up to two full years). |
The clutch supplied by Keisler is an 11-inch, 450 ft-lb-rated high-performance unit made by Sachs. The 168-tooth billet flywheel is CNC-machined, balanced, and has a hardened ring gear for more durability. The one in the picture is a counterbalanced unit for an externally balanced engine. The Transmission arrived with the slave cylinder already installed so that saved us some work. Also pictured is the clutch master and reservoir. |
Next thing was to swap in the new pedals so we could install the clutch master in the proper location. The pedals came with the kit and saved us a phone call to a reproduction parts house. If your car already has a manual transmission, you get to skip this step. |
It was time to mount the clutch master cylinder through the firewall. On most cars, there is a hole for this covered by either a small plate or a rubber grommet. On our '76 there was no factory hole in the firewall, so we got out the drill. |
The clutch master mounts from the engine bay into the interior. On our car this was not an easy task due to all the parts in the way, mainly the power booster for the brakes. We would have to say that mounting the clutch master is the most difficult part of the install. |
We ended up having to elongate the hole just a bit due to the angle of the clutch master. We then marked the bolt locations and drilled three 5/16-inch holes that are used to attach the clutch master to the firewall. Next, we attached the adjustable clutch rod to the new clutch pedal. |
The hydraulic clutch master is self-bleeding and we mounted the reservoir to the brake master cylinder, using the bracket provided by Keisler, where it will be easy to fill with fluid. We attached the hose from the reservoir to the clutch master using a small hose clamp, then filled it with brake fluid. |
To figure out where to cut the transmission tunnel for the shifter, we attached the bellhousing to the engine, then raised the transmission into place. After marking the spot where the shift lever touched the tunnel, we drilled a small hole through to the interior so we could tell the center point of where the opening needed to be. |