FAQ Regarding Cobra Drivetrain Setups

[blykins]

I get quite a few questions everyday regarding different clutch/bellhousing/transmission setups. I thought it may be helpful to start a thread so that everyone can reference it when needed. We can also add to it as we go.

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Q: What is the difference between the TKO 500 and the TKO 600?
A: The TKO 500 is rated for 500 lb-ft of continuous torque. It features a 1-1/16x10 (same as your small input Toploader) input shaft and can be ordered optionally with a 1-1/8x26 input shaft. It has a 3.27:1 1st gear and a .68 overdrive.

The TKO 600 is rated for 600 lb-ft of continuous torque. It has a 1-1/8x26 input shaft. 1st gear is a 2.87:1 and you have two choices in overdrives: a .64 and a .82.

Q: Should I buy the TKO with a .82 overdrive or a .64 overdrive?
A: This depends on a lot of variables: 1. Where do you do your most driving? On a 55mph road or a 70mph interstate? 2. What's your rearend gear ratio? 3. What size rear tires are you running? 4. What size engine and what camshaft are you running?

This is really a customer-dependent question and it really needs to be addressed on an individual basis. Things like rearend gears and camshafts really play a big part in what overdrive is needed. You don't want to pull an engine down to 1800-2000 rpm with a rather lumpy camshaft. Your engine won't be happy.

Q: Why are TKOs offered with "short input shafts"?
A: A lot of guys are running stock bellhousings, Lakewood Toploader bellhousings, or Quicktime Toploader bellhousings. The input shaft on a Toploader is much shorter than a standard length TKO input shaft. To cure this, you can either use a bellhousing spacer or buy a TKO with a shortened input shaft. I'm not a fan of bellhousing spacers. If you're a Lakewood owner, you know that it's sometimes very hard to get them dialed in correctly. When you add a bellhousing spacer to that, you're stacking manufacturer tolerances and could be adding to your bellhousing misalignment. All in all, the price is about the same with either direction that you go.

ALWAYS check input shaft depth.

Q: Lakewood or Quicktime?
A: Both bellhousings are great bellhousings and up until several years ago, the Lakewood was the bell to have. However, in terms of weight (Q/T usually weighs HALF of what a Lakewood weighs), size, quality of manufacturing, and product availability (Need a blowproof bell for a Flathead V8? What about an FE to C4?) , the Quicktime wins hands down in my opinion.

Q: Do I need an SFI bellhousing?
A: I would recommend a blowproof bellhousing with any high performance application. With a brittle cast iron or aluminum bellhousing, there's not much between an exploding flywheel and your leg if something were to happen.

All the Lakewood bellhousings are explosion proof and come with an SFI decal.

The Quicktime bellhousings are offered in both SFI and non-SFI versions. HOWEVER, even their non-SFI bellhousings are able to contain a flywheel/clutch explosion at 10000 rpm. The only difference between their non-SFI bells and their SFI bells is that the SFI bells are bolted around the bottom perimeter and have the SFI decal. If you're racing at a sanctioned event, you'll need the decal. If you have a street Cobra and want the protection, you're more than likely going to have to cut the bottom inch off of a Lakewood or Quicktime SFI bell anyway for ground clearance, so just go with the non-SFI version.

Q: I'm running a big input Toploader and want to switch to a TKO 600. What all do I have to change?
A: You can keep your bellhousing and use a TKO with a shortened input shaft. You will have to change your clutch fork, throw out bearing, pressure plate, and clutch disc. There are 11.5"/12" pressure plates/clutch discs available for both 1-1/16x10 and 1-1/8x26 applications, so it's easy to find a combo that will bolt back up to your 427/428 flywheels.

Either the TKO shifter will need to be relocated or your shifter hole will need to be trimmed. Shifters are available to move the TKO handle up to 4" in almost any direction, so finding a different shifter is not a problem.

Q: What is the best aftermarket shifter for the TKO?
A: I really like the Steeda Tri-Ax. It has adjustable stops and is spring loaded for speed shifting. The MGW and the Red Roberts shifters are also nice pieces and the Roberts shifters can be custom ordered to put the handle exactly where you need it.

Q: How well does a TKO shift?
A: If you're used to a T5 or a Toploader, the TKO will be a little different for you, especially at first until it's broken in. Some of this is due to the shifter that comes with it, some of it is due to the preparation of the parts inside. We offer a "Sure Shift" option to the TKOs to help in this, where the transmission is disassembled, the surfaces of the engagement cones are enhanced, synchros and sliders are deburred, and the countershaft is reshimmed. If you buy a brand new TKO with this option, it will still carry the full factory warranty.

Q: Can you add to the torque capability of the TKO?
A: Yes, we offer a couple of different options to help the TKO hold more torque. We can effectively increase the torque capacity by about 10%.

Q: What clutch kit do I need?
A: This is one of those questions where you have to have every piece of the puzzle to answer. I would start by asking:

1. Is this a street car, street/strip, or race car?
2. What kind of pedal pressure can you tolerate?
3. What is the rearend ratio?
4. What transmission are you running?
5. What engine and flywheel are you using?
6. How much horsepower is your engine making?
7. Do you ever drag launch on slicks?
8. What method of clutch actuation are you using?

There are lots of different variables on picking the perfect clutch. A lot of guys with small blocks like to just pick the King Cobra clutch and find that several thousand miles down the road, the clutch is slipping and worn out. You need to match the clutch to the capability of the engine. You can get away with a little more on a Cobra since most of the cars weigh around 2500 lbs. Usually the tires will lose traction before a clutch has time to slip. However, a stock replacement clutch just won't cut the mustard on a 450-500 hp engine.

Pressure plates are offered in both diaphragm (multiple finger) and Long (3 finger) styles. Both style are available in a wide variety of clamping force arrangements. Generally, the Long style clutch will have a higher pedal pressure, but this always doesn't hold true and there are definitely ways around it.

Clutch discs are offered with many different friction materials, styles, and hubs.

Your typical stock replacement disc is a sprung hub disc with a full circumference of friction area and is made of an organic material. This is the disc that offers the very best street manners (no chatter or quick engagement) but will hold the least amount of power. You can upgrade the pressure plate to help with this, but you're limited to about 450hp unless you go with a twin disc setup.

From there on up, you run into Kevlar discs, sintered bronze, sintered iron, ceramic, paddle discs, non-sprung hubs, etc, etc.

Each combination of pressure plate and disc will give you a certain clutch capability and degree of streetability. It all can be custom matched to suit your specific application.

If you have a specific question to your situation, feel free to contact me. I can answer any question that you have.

Q: Can I run a really light flywheel and a button clutch on the street?
A: I get lots of questions about lightweight aluminum flywheels and clutch kits.

You'll get differing opinions, but here's my thoughts: I try to keep the weight down off the end of the crankshaft. However, there's a diminishing return when you run too light of a setup. An extremely light setup will cause you to have to slip the clutch a little more to get the car moving. On a Cobra, this isn't too big of an issue. However, you can tell the difference between a 35# flywheel and a 14# flywheel.

The difference is in the rotating momentum. When you're not slinging as much weight back there, the engine has to make up for it when you're trying to get a lot of weight moving. This is also application dependent and I would not recommend a 14# flywheel for a 302 with a 3.08 rearend. However, for a 428 and a 3.70, then I would probably say go for it.

On the button clutches: These are very light weight setups made for circle track or road racing. Most of them are 5.5" to 7.5" in diameter and are only available with very aggressive non-sprung discs.

When you combine hardly any rotating momentum with an aggressive disc, you find yourself having to dump the clutch to get the car moving. An aggressive disc will not slip at all....it's a light switch on engagement: on or off. When that happens and you have no rotating momentum, it makes for an interesting start from a red light.

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I encourage anyone to call (502.759.1431), PM, or email me with any questions. If something else needs added here, I'll be happy to append some info.

I'm a dealer for McLeod, RAM, Hays, Lakewood, Quicktime, Moser, Strange, Wilwood, Fidanza, PRW, and Tremec. All parts and combinations are usually available and ready to ship, unless it's a custom built transmission.

I'm also an engine builder and offer many different small block and big block (385 and FE) engine combinations. Again, contact me with any questions that you have.