Tremec TKX 5-speed?

[kcombs]

Has anyone installed a just released TKX 5-speed? The new tranny looks like a good fit for a 65 GS. I am thinking of making a deposit to reserve one for when they start shipping. Now I have to decide on a couple of different gearing options....... I will be using an original four speed clutch and bell housing setup, I am not converting from an automatic.

[WkillGS]

I don't have a TKX but do have a Richmond Street 5 speed.
The Richmond is a close ratio with 3.26 first gear and 1:1 5th gear.

I would prefer a wide ratio. You don't need to shift as often and it takes better advantage of the Nailhead torque.

The wide ratio TKX 3.27 first gear would work better with a 2.78 to 3.08 rear.
The close ratio 2.87 first gear would like a 3.23 or up. 
This is because of the resulting 'starting line gear ratio'.... it's just the rear ratio multiplied by the first gear, such as:
TKX wide with 3.27 first:
2.78 rear => 9.09 starting line gear ratio
3.23 rear => 10.56 starting line gear ratio
TKX close with 2.87 first:
3.23 rear => 9.27 starting line gear ratio
3.55 rear => 10.19 starting line gear ratio

A 'starting line gear ratio' of 9-ish or below means it'll take a little more clutch slipping to get the car going. A ratio over 11 makes first gear almost unnecessary for street use.... you could start out in 2nd gear.

You can also compute the highway rpm with different gear/tire sizes with a calculator:
http://www.wallaceracing.com/calc-gear-tire-rpm-mph.php

[kcombs]

Wow Walt, thanks for the awesome response, now I just have to figure out my rear end gearing. If I remember correctly the usual gearing for a four speed was 3:36, or close to it. Just thinking, if I go taller gears, it will slow the drive shaft down, not a bad thing.

[WkillGS]

Hey Kurt, there's a thread over on V8 on the TKX. Michael posted a couple of times there, he'll likely get back to you here with his experiences and recommendations.
https://v8buick.com/index.php?threads/new-tremec-tkx-5-speed.362992/

[TrunkMonkey]

Happy to answer any questions that I can. :)

I have the wide ratio and 3.54 rear.

The greatest wear on a clutch is starting off, and using engine breaking on down shift.
 (Normal driving. dumping the clutch and high RPM power shifting being the exception)

I rather change brake pads than pull the tranny and do a clutch change as the cost of parts and effort are so much greater.

So, the 3.27 1st is very easy on the normal start, you get great 60 foot launches, and if you want to "have fun" a 3000 RPM, 130' second gear launch and smoke show is a hoot.

[Matty67]

Kurt , did you ever pull the trigger on the TKX transmission?

Rick

[Rollaround]

Short sidenote. I just installed a TKX in my 65 GS, though not behind a Nailhead it fit like a glove. I moved the crossmember back 1.5" and dropped the trany mount pad down .5". The only cutting was slight enlargement of the auto trans opening for the shifter. I think I could have gotten by without any modification however, I wanted the engine trany combo moved back as far as possible. 

[kcombs]

I have not started that part of the project yet.

Kurt

[GS66]

They had a nice display of these on the Power Tour. They look like they will fit with minimal issues and even line up so the shifter can be used with the consolette. Certainly looks like a great way to go!