First it was the lowly three-speed. Then came the classic four-speed. In the 80s, the five-speed was the rallying cry of the manual transmission crowd both from what was then the Doug Nash as well as the OEM T5 from Borg-Warner. But the T5 was weak and never enjoyed popularity with manly, high-torque gear bangers. But now theres a new kid in town: the Borg-Warner T56. Chevy realized it had to have a gearbox strong enough to take on the power of the LT1, LT4, and the new LS1 small-blocks and chose the T56.
For hot rodders and Chevy enthusiasts, this trans has been in production long enough that used boxes are beginning to appear on the market. The lure of a strong overdrive transmission is so great that a few enterprising individuals have taken on the task of battling through the background of misinformation and details needed to swap one of these transmissions into an early Camaro, Chevelle, or Nova. Pro Tourings flag waver Mark Stielow recently swapped one of these boxes into an early Camaro.
We followed along to get the information, but as we waded into the murky T56 swap swamp, it quickly became very sticky. This story will hit the high points only, because this conversion is somewhat complicated. Before you start spinning wrenches, you need to know the best transmission for your application. Then you can start working on the details of stuffing this box into an early Chevy. Stick with us, its worth the effort.
There are several stock T56s, plus an aftermarket version. The Borg-Warner six-speed transmission is like a four-speed with two additional overdrive ratios. The ratios vary, but Fourth is always 1:1 with most offering a 0.74:1 overdrive in Fifth, and Sixth at 0.50:1. The most common sixspeed is in the 94-and-later Camaros with a 2.66 First-gear ratio. To compare it to a Muncie four-speed, thats 0.12 deeper ratio than the wide ratio. That means that you dont need a real deep rear gear to make this box fun. Theres a reason why the factory went with a 3.42 rear gear ratio. A good choice would range from 3.30 to 3.73 and would be ideal for a street-driven Chevy. The first-year 93 Camaro used both 2.97:1 and 3.36:1 First-gear ratios with a 0.62:1 overdrive. These boxes are rare (especially the 3.36 version) but should be avoided anyway since they offer a lower torque capacity.
The very first T56 into production was designed for the Chrysler Viper sports car. This box has the same overall case length as the Camaro transmissions, and has the same ratios, but uses a larger diameter input shaft and a 30-spline output shaft. The Camaro box employs a smaller 26-spline input shaft (same as the Super T10) and a 27-spline output shaft (similar to a TH350 or Muncie four-speed). According to Stielow, the weak link is the stock output shaft, especially if its subjected to slicks and lots of torque.
The T56 is also stock in the new C5 Corvettes, but this box is incorporated into a transaxle design. While it might be cool for a street rod, its much too complicated to get into adapting the transaxle into a Camaro or an early Nova. Well save that for someone whos really adventuresome. The six-speed used in 89-96 Corvettes was the ZF, a German-built transmission that is a whole different animal. While its durable, the details for swapping that box would require an entirely separate story. Given the choice between a ZF or a T56, all our sources say you should choose the T56.
There is also an aftermarket T56 transmission available through selected Chevy dealerships like Burt Chevrolet. This transmission was designed as a direct replacement six-speed for 82-92 Camaros to replace the weak T5 five-speed used behind the 305 engine. This transmission is intended to be a direct bolt-in, using a T5 bellhousing and clutch assembly. This trans comes with a longer input shaft to mate to the deeper T5 bellhousing, along with a ½-inch-thick steel plate that bolts between the trans and the bellhousing to adapt the T56 bolt pattern to the T5 bellhousing.
This ½-inch-thick 19-pound plate adapter can also bolt the T56 to a standard early mechanical clutch linkage bellhousing like a scattershield, but it requires redrilling the plate, something that should be left to a machine shop. This plate system can work in an early Camaro but does require minor trans tunnel surgery to clear.
The stock Camaro box out of a wrecked 94-or-newer Camaro is the transmission most Bow Tie enthusiasts should use. Well outline a couple of different ways to approach this swap, but in virtually all cases, the cost will approach $2,500. If you are contemplating this swap, you need to consider all the variables before you lay out the long green for a transmission, even if you can buy a used box for less than $1,000, which is a good deal.
Stielow thinks the easiest way to go is to seek out a used 94-or-newer Camaro/Firebird transmission, clutch, pressure plate, and flywheel assembly mated to a late-model one-piece rear main seal small-block. This would mean an engine like an L98 TPI engine, or an LT1 (which could be converted to carburetion). Another great idea would be either GM Performance Products ZZ4 or 350 H.O. engines. The key here is the one-piece rear main seal that allows you to bolt up the factory flywheel, clutch, and pressure plate assembly inside a stock LT1 bellhousing. The only tricks involve adapting the hydraulic clutch master cylinder to the firewall, modifying the rear trans mount or location, and shortening the driveshaft.
As an example, Roger Conley just performed this exact swap in his early Camaro. He used a ZZ4 carbureted small-block combined with a T56 trans from a 96 Camaro. By doing so, he avoided the need for a specialty flywheel. He also used the stock LT1 bellhousing, flywheel, clutch, pressure plate, and hydraulic clutch mechanism straight out of the donor 96 Camaro. According to Conley, he moved a stock 69 Camaro TH400 crossmember back to the rear hole on the subframe to mount the crossmember. Then he modified a TH400 rubber trans mount to bolt to a stock vertical T56 torque arm bolt hole. According to Conley, there are probably better ways to do this, but it worked for him. When Conley bought the transmission, he also bought the Camaro driveshaft and had it lengthened with a new tube to bolt to the 9-inch Ford rear in the back of his Camaro. He could have also shortened the stock early-Camaro driveshaft, since the overall case length on the T56 is about 3½ inches longer compared to a Muncie.
The biggest contention with this swap is the location of the T56 shifter. Conley is 6 feet tall and prefers the drivers seat all the way back. With the trans in the car, Conley elongated the shifter hole in the floor of his 67 Camaro to clear the T56 shifter. He preferred the shifter farther back, so he cut 2 inches off the bottom of an old Hurst Competition Plus curved stick and redrilled the holes to bolt directly to the T56 shifter stub. Conley then slid the console back to cover the shifter and the result looks almost factory. What are the disadvantages? One hassle is that the production T56 trans uses an electric speedometer drive mechanism. The easy fix here is VDOs electric speedometer, which is easily calibrated and will work directly with the factory transmission. Ideally, youd want to combine this with a VDO tach, which adds more money to the swap, but it does offer an easy addition for the speedometer. Jaguars That Run also offers a conversion to run a mechanical speedometer drive for T56 trannies. T56 tailhousings are modified on an exchange basis, and Camaro T5 speedo gears are supplied.
John Wilsonanother Bow Tie swapperperformed a similar trade in his early Camaro. In his case, he preferred to maintain the 67 Camaro console in the stock location. This necessitated using an aftermarket extension housing that moves the shifter location forward about 23/8 inches. Wilson then fabricated a dog bone shifter adapter that moves the stick another 2 inches forward to place the shifter in the stock location. The disadvantage here is that the aftermarket extension housing is an expensive addition to the cost of a used transmission.
If the one-piece rear main seal engine is not an option, theres still a way to make this swap work. To use an earlier, pre-86 two-piece rear main sealstyle small-block engine, you must use a custom flywheel. Centerforce offers a custom-machined, steel 153-tooth flywheel that will bolt to the two-piece rear main seal crankshaft flange that works with the required pull-off 11-inch clutch assembly inside a LT1 bellhousing. If you need a clutch as well, Centerforce can make all this happen with an excellent Dual Friction assembly, but suggested retail on this is just over $700 (not including the flywheel). A Centerforce 1 package uses a conventional clutch disc that, with the pressure plate, goes for just under $600 retail. These are pull-off clutches, which are relatively new, and thats one reason for the higher price. While weve not gone into the details on a big-block, Centerforce also builds big-block flywheels to mate to a T56 as well. Yahoo!
If youre still with us after all this, you can see that trans swapping is not as simple as it was with Super T10s and Muncie four-speeds. In a later installment, well get into more detail on the actual swap. While its fairly straightforward, it does involve some fabrication work. The good news is that once youve made it work, this is one sweetheart of a transmission.