Gearing and Rear Discussion TKX

[Bighouse]

8K?, I thought @Kern Dog said it was around 6K

He got it on sale or something

 

[furious70]

My 2 cents having a wide ratio tko and a lumpy cammed 440, 4.10's and 28" tires.
The .68 OD is too tall unless I'm doing 75+ and 60 is buzzy in 4th with 4.10's as we all know.
And granny gear is low.
I'd rather have a close ratio and .82 I think. I'd like to try it at least.

 

[pnora]

My 2 cents having a wide ratio tko and a lumpy cammed 440, 4.10's and 28" tires.
The .68 OD is too tall unless I'm doing 75+ and 60 is buzzy in 4th with 4.10's as we all know.
And granny gear is low.
I'd rather have a close ratio and .82 I think. I'd like to try it at least.

A lot will depend on how strong the motor is. My hemi has low torque 588TQ at 3,100 rpms. so it pushes it along great with the .68. I imagine a lesser producing motor will have maybe less desirable performance. The whole idea behind the overdrive is to give you less RPMS. Its not a performance gear.

 

[furious70]

My 440 doesn't make that tq at any point =)
Loping along at 2000rpm with 440" and my cam just is not in the right range

 

[Kern Dog]

In my opinion the .68 is too steep. I believe the .82 to be more versatile.

The bigger the engine, the less cam you need to make the power. I have the .64 OD the TKO 600 has. I've driven it with the 528 and the Lunati that is much bigger. While the engine did a bit better at 1800 with the smaller 528, it still does fine with the Lunati at that speed. The engine is a 440/495 so the cubes make that possible. Cams this big with 440 cubes may be a different matter.

8K?, I thought @Kern Dog said it was around 6K

Mine was the last of the TKO 600 kits they had in stock.

He got it on sale or something

Maybe, maybe not. I think they were seeing other buyers skip over the TKO to buy the TKX and when I called, they were glad to find that I was interested in the one the others didn't want. I wanted it because it was a proven design. The price was just shy of $6000. This was over 2 1/2 years ago before the wave of inflation came through. That **** affects everything.

 

[rirealtor]

Appreciate ALL of these responses and discussion of different real world experiences. My guess is that the first year will be a bit of a break in period for everything, so may wait until next winter for a swap.

 

[magster65]

My 70 has a 440 833 8.75; I had 4.10's in it with 27" tires. It was great banging through the gears around town but on the highway it was buzzing up around 3300 rpm... no good in my books. We planned a group road trip so we swapped the 4.10's out for 3.23's and 28" tires. As expected the car was great on the highway (2500rpm+/- @ 65 mph) but it definitely paid the price in lost acceleration. This experiment makes it an easy decision; I'm keeping the 28" tires (275/60) putting the 4.10's back in it and I'm saving for the TKX 5 speed conversion.
My Belair (don't hate me lol) has a TKO 5 in it with 27" tires (255/60) and 3.5's, it's about a little under 2000 rpm at 65 mph. I use these calculators:
Tire Size Calculator
Calculate RPM for Given Speed(MPH), Rear Gear Ratio, and Trans Gear Ratio
Cheers