[Formulajones]

Yes, from my experience with various size engines and brands, that's a nice place to be that returns good mileage, less noise, and still enough grunt with any engine to pull any grade without the need to look for another gear.

I like to shoot for 70-ish mph at that rpm range in overdrive. That way on the long trips where speed limits are 75 and I want to cruise 80 I'm still not pushing the engine very hard at 2200 or so, and it still gives me respectable mileage at those speeds.

The problem I have with the new TKX now is they are starting to creep up the OD gear to .68 which is causing me to readjust and rethink the final gear ratio to keep my MPH and RPM where I want it to be. If they are going to do that then I want the 1st gear ratio a little steeper so I can knock some rear gear out of it. They would have been better served to play with the 2-3 gear ratio and leave the overdrive alone. However the .68 overdrive would work well for those that run 3.23 gears like the OP, this trans will fall right in your wheel house. I start to not like it as much with 3.73's or more.

That's one reason that now really has me leaning towards the muscle car trans (McCloud) which is T-5 based with stronger gears and case. I went with a Promotion version of this trans, (good for 600hp) and absolutely love the gear ratios.

[Scott Stoneburg]

So to make the swap to the TKX 5 speed, what is all necessary to change?
*Shifter
*Driveshaft
*Clutch?
*Will it bolt to the existing bell housing?
*Trans crossmember?

[Formulajones]

Already a 4 speed correct?

Shifter body for the TKX (will accept any bolt on hurst stick) So if the car has an aftermarket Hurst in it already, the stick will transfer over.

You'll at minimum need the yoke, which then can be used if you want to shorten the existing driveshaft. That's the cheapest route, if you have a driveline shop nearby to do the work. Otherwise buy a new driveshaft with correct yoke. I tend to like a new driveshaft anyway, something stronger.

For the clutch, if running a 10 spline now, you can get away with just replacing the disc to a 26 spline. Again, cheapest way to go, I find most clutches on these classics that don't get driven much are in really good usable shape and just swap out the disc and go with it. If already running a fine spline muncie, nothing needs to be changed.

Yes bolts to existing bellhousing

Trans crossmember is optional. Usually I fab up the existing cross member. If you have the ability to do that it saves money. If that's not an option and you want to save time, and not monkeying around with driveline angles, then there are several on the market made for this swap.

Another piece I like to buy is the short speedo cable adapter that extends your current cable and has the Ford style speedo end on it. All these Tremecs still use the Ford style speedo adapter and gears..

One other little piece I like to have is the pigtail for the backup lights. A harness can be made yourself to run the wires but I find it's much nicer to buy the short pigtail that already has the correct weather tight rubber seal to fit the Tremec at the connector, and they don't cost enough to squabble about.

That pretty much covers a swap for a car that is already a 4 speed. Pretty straight forward.