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If you’re looking to inject some contemporary performance and drivability into your vintage machine, swapping in a modern transmission is one of the most effective ways to really transform its behavior. The additional cogs can allow you to run a more aggressive rear end ratio for better acceleration while still allowing for low-RPM highway cruising in top gear, and modern technology has made these gearboxes both stronger and easier to live with than anything that was commonly available decades ago.
The Tremec T-56 six-speed manual transmission has become the go-to gearbox for swaps in a wide variety of different vehicle platforms thanks to its design, strength, and wide availability, but there are situations where Tremec’s five-speed transmissions like the TKX, TKO, and T5 might ultimately be a better option. “If horsepower and torque handling are the biggest concerns, people usually go for the six-speed,” says Brian Gaines of Holley Performance. “But these five-speeds offer a big advantage in terms of their size – they’re much smaller, so that makes any packaging concerns less problematic. And now that gearboxes like the TKX are available, which can handle up to 600 pound-feet of torque and 8000 RPM, people are turning to these five-speed transmissions in situations where there’s not a lot of room for that big six-speed. The five-speeds are generally lighter, too, so that’s another benefit of going that route.”
Installing a five-speed manual transmission into just about any vehicle offers a broad spectrum of improvements: they are smaller than six-speed, they are lighter, and they can handle stout power output.
With that in mind, Holley recently introduced a line of Tremec installation kits for builders that are looking to adapt one of these modern five-speed gearboxes to an old school GM or Ford power plant. “I think the real push here was to address a gap in our product line,” Gaines explains. “We already had most of the components in the kit ready to go, and we wanted to get onboard with the new, badass transmissions that are available today.”
Targeted mainly at street and mild street/strip applications, the kits include everything you need to get one of these Tremec gearboxes hooked up and running. “The big win for builders here is the fact that you don’t have to look for all of the different parts you’ll need to make this work,” he says. “It’s one-stop shopping, and you know it’s all going to work well together right out of the box.”
Holley's Tremec Installation Kits will provide you with everything you need in order to mate a T-5, TKX or TKO five-speed manual transmission into your project.
The kits include a cast aluminum bellhousing and steel block plate to provide a factory-like installation process and appearance. “These bellhousings were produced by Lakewood Industries, one of our sister brands,” Gaines points out. “They were actually developed before these kits came together because of demand – a lot of the crate engines have been sold over the past few years, and a lot of the original bellhousings are getting hard to find these days. This solves that issue.”
A balanced billet steel flywheel is also included in the kit in order to keep the mass low and the durability high, and Hays was tapped to provide the high performance clutch for these installation kits. Rated for up to 500 horsepower, these clutches use an organic composite friction material and feature a heavy-duty hub spring assembly for increased load capacity. “It’s one of our newer setups,” Gaines notes. “It should deliver about 30% more clamping pressure than a stock clutch would in this type of an application. That translates to increased power handling, and that should allow you to get more of that power to ground.”
Holley's Tremec Installation Kits feature an arrangement of parts that work together to make a stout combination, including Lakewood bellhousings and Hays high-performance clutch kits (pictured).
Holley paired the clutch with a hydraulic throwout bearing to reduce pedal effort and improve drivability as well. “In systems that use a mechanical throwout bearing rather than a hydraulic one, you have a component called a Z bar, which bolts up between chassis the engine,” says Gaines. “When you push in the pedal, you have a rod that’s connected to the Z-bar that actuates the clutch. There’s a lot of mounts and moving parts involved, and it can be really finicky to deal with. If the Z-bar isn’t straight because you’ve got a solid-mounted engine that’s moved for some reason, you’ve suddenly got bad geometry and more wear points. Any time you can eliminate that Z-bar – as well as the forks and linkages that are associated with it – you’re reducing the potential for a lot of headaches, and going with a hydraulic throwout bearing allowed us to do exactly that.”
The kits also include a roller-style pilot bearing to improve shift quality by reducing parasitic drag and transmission wear in turn, along with all of the hardware and tools you’d need to get the job done from start to finish. “And that goes right down to stuff like clutch alignment tool and the bleeder line for the throwout bearing,” Gaines points out. “The shims, flywheel bolts, transmission bolts, bellhousing bolts – it’s all there. The hardware can be some of the hardest stuff to track down for a project like this, but this is a truly complete kit. If you’ve got the engine and the transmission, this kit includes everything that you would need to bolt the two of them together.”
Installation Kits are available for a range of Ford and GM applications, and more kits are in the works, including Mopar engines.
These installation kits currently support the Tremec TKO and TKX five-speed transmissions with a range of GM and Ford engines that include 1955 to 1985 internally-balanced Chevy small-block and big-blocks as well as an array of Ford small blocks, and Holley also offers a kit that adapts the Tremec T5 to a 28-ounce, externally balanced small block Ford engine as well. But Gaines is quick to point out that this product line – which just launched earlier this year – is still in its infancy, and support for other engines is coming down the pike sooner rather than later.
“There are more engine applications coming – we’ve got a number of them in the works right now, and support for some of the Mopar engines is part of that. Since these are kits put together with existing parts from across our various brands, it really comes down to the development and production of the new bellhousings.”
Although the kits aren’t designed to allow builders to mix and match components, he also notes that in situations where you might want, for instance, a kit that can handle more torque, Holley can accommodate that as well. “These kits used matched components – the specific clutch, pressure plate, flywheel, and other components in a given kit have all been selected because we already know that they will work perfectly together, so it’s not really an a la carte kind of deal,” adds Gaines. “But, of course, we have just about anything else you could want to use outside of these kits, so a ‘custom’ kit could also be put together for a specific application if need be. All a builder would need to do is just call us to get that sorted out.”