66fstbk88

After looking at all my options, Ive come down to going the TKO route.
I was looking at the new TKO 500 and they have a 10 and 26 spline input option. I'm confused about is, what is the difference between between a 10 spline input and 36 spline input?
I know a stock T5 like the one I currently have are 10 spline input but every time I hear bout people having TKO's in their classic, seems they always mention how they had to convert to a 26 spline clutch as well?
Is one better than another?

67mustang302

The larger spline is a stronger input shaft.

66fstbk88

either way i would have to have to get the input shaft shorten to fit my application. So the benefit of 26 spline is that its stronger. is it a big difference?

Norm Peterson

I thought the TKO 500's were 10-spline and the 26-spline went with the TKO 600's.

If you aren't drag racing, a TKO 500 should be more than plenty at least up to 350-ish normally aspirated cubic inches. I have a 3550 (375-ish ft-lb rating, now superceded by the TKO 500) behind an EFI 355 SBC and it's held up just fine for hard street driving and autocross. No drag strip activity though (not my game).

Supposedly there are three different input shafts to choose from, but I don't know what the differences are.


Norm

1971mach1

There's first gear ratio to concider also when choosing btw the TKO-500
and TKO-600. The 500 has a 1st gear of 3.27 and the 600 has 2.87.
If you have a rear gear numberically higher than about 3.27, you'll want the 600.
Otherwise 1st gear will be like a "granny gear" and RPMs will wind up too quick to be useful.
I have a 3.00 rear gear and went with the TKO-500 because I didn't want the expense of changing rear gears too. It turned out to be a great combo.

67mustang302

Yeah, gearing is different, also there's a difference with 5th gear. The 600 is .64 and the 500 I think is .68 for overdrive. You'll need the Ford input shaft length and a TKO bellhousing though.

As far as the power ratings, the thing you need to understand about them is the torque rating is the maximum CONSTANT torque input the trans can take and survive in it's expected lifespan. No one knows for certain because the engineers are the only ones who really know, but supposedly the lifespan at the constant peak torque rating is measured in the thousands of hours. In other words a TKO 500 should be able to hold 500lb-ft of torque CONSTANTLY for 1,000+ hrs before mechanical failure occurs, primarily due to fatigue/heat. In a street car you spend 99% of the time producing very little power, so the lifespan of the trans goes way up. That also means you can put even more power through it, but it has a shorter expected lifespan at higher ratings. The 2 biggies that kill a trans are heat and shock load. Running it too hard for too long generates too much heat, so it fails, and short bursts of high power don't build up heat provided it has some time to cool down. Shock loading is when you suddenly transfer a bunch of power to the trans, like dumping the clutch at high rpm with a drag slick for instance. In cases like that a 400lb-ft engine can spike and generate an instant torque load measured in the thousands of lb-ft through the trans.

All that said, there's many a TKO behind drag and road race engines producing more than the "rated" torque, and they haven't failed.

The main differences with the TKO's besides the power rating and gear choices, is input/output shaft selection...GM, Ford, Mopar etc.

JMD

TKO 500 or TKO 600 can be obtained with either 10 spline or 26 spline input shaft.

The stock TKO (unshortened) input shaft will work with a TKO speciffic bell housing or with a commonly available TKO speciffic bell housing adapter. (simple is good!)

The 26 spline shaft is stronger, but I ordered the 10 spline input on the 66 (probably not a good choice on my part) because the clutches were about 1/2 as much for 10 spline as 26.

We used a TKO speciffic lakewood scattersheild, late 5.0 clutch, and Mustang Steve clutch cable without complication.

67mustang302

Yeah, there's a lot of different possible combos with a TKO, since it's a universal aftermarket deal. I've found the Centerforce Dual Friction clutches are about the same cost whether they're 10 or 26 spline, since it's a common clutch for both sizes.

On my setup I'm running a McLeod hydraulic clutch setup for TKO/Toploaders, with a Quicktime SFI bellhousing and a 26s Centerforce DF.