So far, our Project Blank Slate 1969 Chevy Camaro, which is being built to be a street/autocross car, has seen a number of upgrades since it was brought into the Power Automedia shop as an empty shell. The major work so far has included having an LME 500+ hp LS V-8 built, a Chris Alston’s Chassisworks and Wilwood brake setup installed, and Forgeline Wheels for the project. And although we have nothing but respect for the classic Muncie rock crusher, we wanted to bring our ’69 Camaro into the 21st Century with a contemporary transmission to complement its modern LS-based engine.

The only way to accomplish this fast-forward to a modern-day transmission for our classic Camaro was with a conversion kit, and one of the best on the market for this application was from American Powertrain. Gray Fredrick from American Powertrain told us, “What makes our conversion kits great for hot rodders is that you don’t have to go looking for parts, they are a soup-to-nuts deal, that’s our thing.” We paired the conversion kit with a twin-disc Advanced Clutch Technology clutch kit engineered to handle more than 800 horsepower.

While an automatic transmission would have been an easy choice, we definitely wanted that old-school feel of rowing through the gearbox, even though it would mean throwing the lever a couple of extra times with a TREMEC T56-Magnum six-speed. With a high-gear overdrive ratio of about 0.64:1, the six-speed TREMEC lowers the cruising rpm at 70 mph by about 1,200 rpm in a classic Camaro with a 3.73-geared axle compared to the typical M-22 Muncie four-speed. That means a reduction from about 3,300 rpm to about 2,100 rpm, which improves fuel economy, cuts interior noise and reduces engine wear. What’s not to like?

TREMEC’s venerable five- and six-speed internal-rail manual transmissions have been behind factory Camaro small-block engines since the mid-’80s, delivering a great balance of performance and efficiency. In an early Camaro, those admirable qualities are enhanced immensely by the vast improvement in drivability.

In the fifth-Generation Camaro, the company’s newest six-speeds are direct descendants of previous models, but upgraded for the higher torque capacity of the latest LS engines – including the TREMEC TR6060 transmission used in the supercharged Camaro ZL1.

In fact, TREMEC’s aftermarket T-56 Magnum transmission marries the heavier duty guts of the TR6060 within the familiar T-56 case. It’s also rated for 700 lb-ft of torque and a 7,000-rpm shift capability, and its pair of overdrive gears – 0.80 (fifth gear) and 0.63 (sixth gear) – enhance the cruising speed options around town, too. Additionally, the gear ratio spread is better matched to a higher-power, high-rpm engine, such as our Camaro’s LS engine.

As for the obvious thought of adapting a Fourth-Gen’ F-body T-56 found on craigslist for a couple hundred bucks: forget it. It’s not a direct fit with most aftermarket conversion kits on the market, because the production tail shaft is about three inches shorter than the T-56 Magnum and the shifter position isn’t the same, either.

Also, the T-56 simply isn’t as strong and it doesn’t offer some of the swap-friendly features of the aftermarket-intended Magnum. Technically, yes, you could make the production T-56 work, but the project would end up costing more time and trouble, so our advice, is to spring for the T-56 Magnum. You’ll be better off in the long run.

The cost of a T-56 Magnum is around $2,900, which brings the basic parts just under the $3,900 threshold. That’s pretty reasonable when you judge it against, say, rebuilding an old transmission. A slightly less costly alternative would be a TREMEC TKO five-speed kit, but the Magnum delivers greater torque capacity to handle the LS engine.

Swap Basics

Marrying the T-56 Magnum to a First-Gen’ Camaro (or other older cars) requires a few unique parts and likely some floor pan modifications, which is why we went with the dedicated kit from American Powertrain.

Also, it’s definitely easier and less time-consuming to swap the trans into a car that was originally equipped with a manual transmission, but the kits on the market certainly accommodate previously automatic-equipped models.

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American Powertrain provided the Hydramax hydraulic clutch release (far left). We used a twin disc setup from ACT to round out the package (center, and right).

First and foremost, the T-56 Magnum is longer than the average Muncie four-speed, stretching about 28 inches, stem to stern, not including the bell housing. The average M-22 Muncie is roughly 21.5 inches long, without a bell housing. Those differences in length vary by application with the bell housing used in the vehicle, but the bottom line is a longer transmission is going to require a shorter driveshaft (with a 26-spline slip yoke).

Also, using a T-56 Magnum will alter the position of the shifter. The conversion kits have the parts or complete shifter assemblies to accommodate this, keeping the shifter at the stock position in the console, which is yet another reason to go with a swap kit, someone else has already spent the time on engineering and fabrication.

The longer length of the Magnum requires tunnel surgery to make room for the shifter. Even if you use an offset shifter and/or slide the center console rearward, clearance for the shifter mechanism must be created about four inches rearward of the original shifter hole in a manual-trans First-Gen’ car.

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Prior to installing the new clutch, the ACT XACT Prolite flywheel (left) was installed. It is lightweight (only about 10 pounds), admirably rigid and SFI-approved. With the flywheel in place, the clutch kit was bolted on; and the alignment tool provided with the kit made the job of centering the disc and pressure plate a lot easier.

The six-speed trans swap kit from American Powertrain for First-Gen’ Camaros comes with everything needed for a basically bolt-in conversion, including the cross member, trans mount, driveshaft and even a chrome-handle shifter, with a list price of $945.

Additional components of the swap included a rear crossmember to support the tail of the transmission, a speedometer converter, either mechanical or electronic, depending on the transmission, and a pilot bearing. 

Although not included with the transmission installation kit, American Powertrain offers a couple of bell housing options. We went with this lightweight aluminum unit, which lists for $282.45. There’s also a racing-spec, SFI-approved QuickTime bell housing that runs just about $600. 

Ours will be a street car, so the aluminum part will work just fine. You’ll also have to address the possible need (we did not) of an adapter plate between the bell housing and the transmission. You can also upgrade to a hydraulic clutch system. According to Grey Fredrick at American Powertrain, “The hydraulic clutch upgrade is a must-have because it makes the shifting action silky smooth and so much easier on the driver than the stock mechanical linkage.”

American Powertrain carries all the items for complete hydraulic clutch actuation, including this HYDRAMAX hydraulic clutch release bearing, which was installed on the retainer shaft. Shims are sometimes required to ensure optimal clearance between the bearing and clutch fingers. 

For our street Camaro, we went with two of ACT’s Performance Street rigid-hub clutch discs. These have premium organic friction material with steel-backed lining, which increases the high RPM burst strength. The chrome-moly hub is lightweight, which makes shifting action quicker and lighter. It should stand up well to the torque of the LS engine.

Before installing the new clutch, we bolted one of ACT’s XACT Prolite flywheels. We wanted the low-inertia performance it offered over conventional, “full” flywheels. But while it’s lightweight – weighing only about 10 pounds – its admirably rigid and SFI-approved. According to Bernal, “The ACT flywheel, made of forged steel with chrome-moly teeth, is not only light, but also offers great strength, and better clutch response due to less flexing. Our philosophy on flywheels is bolt it on and forget it.” 

With the flywheel in place, the rest of the clutch kit was a snap. ACT includes an alignment tool to properly align the disc and pressure plate. It’s a lot easier to do the job with the engine out of the car, but not too much of a chore if you have to work with the engine already installed. 

With the clutch installed, the TREMEC transmission was bolted to the engine and the entire assembly was gently guided into place in the Camaro’s custom, prepared front subframe. At this point, none of the necessary floorpan modifications were made, as we needed to determine the position of the engine and transmission in the chassis before cutting. 

Having A Floor Plan

Our ’69 Camaro was originally equipped with an automatic transmission, which made the transmission-tunnel surgery a bit more involved. But with the directions supplied in the American Powertrain installation kit, we quickly marked out the position on the tunnel that required trimming for shifter clearance.

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Using a cutting wheel, the floorpan (left) was cut where we had determined the shifter mechanism was located. The new hole in the Camaro's tunnel was cleaned up and inspected (center) to make sure it was large enough for proper shifter performance. Then the TREMEC shifter was lowered into placed and attached to the transmission, and we ran through the gears (right) to make sure the action was smooth and clearance with the hole we had cut was sufficient.

We broke out the cutting wheel and started slicing the vintage tin. We were careful to keep the cutting wheel comparatively shallow to prevent inadvertent damage to the shiny-new transmission below. With the new hole in the Camaro’s trans tunnel, the edges were checked to ensure the shifter position on the transmission lined up.

Next, the TREMEC shifter was lowered in place and lightly tightened. We ran through the gears quickly to be sure the action was smooth and there was no binding or interference with the clearance hole. All was good with our inspection – and it’s much easier to take an extra minute or two to check everything at this stage than find out there’s an issue when the interior is re-installed.

The shifter installation was buttoned up with a custom cover plate on the tunnel, which adds strength back into the tunnel’s structure and also acts as a sound barrier. It’s a natural fit for the Camaro, but there are still more tasks to wrap up the transmission project, including adding a new pedal system, wiring up the transmission and installing the American Powertrain-supplied driveshaft. Our project still has a ways to go, but we’re definitely making progress!

Some Final Thoughts

Removing your Camaro’s existing transmission and swapping in the new trans is entirely possible with the engine still in the car, but it makes the job harder and there’s not as much room to maneuver when bolting up the transmission. If you can do it, remove the engine or, at the very least, tilt the engine rearward for greater clearance. This will likely require removing the distributor cap or the distributor itself to prevent it from hitting the firewall.

Then again, if you’re going to be tilting the engine and removing the distributor, you might as well pull the engine, assuming you have the capability in your garage. If you have access to a lift and proper transmission jack, you’ll be miles ahead and the curse-word count will be greatly reduced.

We were pleasantly surprised at the ease – relatively speaking – at which the whole shebang went into our ’69 Camaro. The ACT clutch bolted up without a hitch, as did the transmission. The quality and thoroughness of the American Powertrain installation kit was impressive, too. Those guys did their engineering homework, and it showed in the straightforward installation. We can’t wait to hit the course and see this beast in action – stay tuned!