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- The 1960 - 1966 Chevrolet & GMC Pickups Message Board (https://67-72chevytrucks.com/vboard/forumdisplay.php?f=6)

- - Tko/tkx (https://67-72chevytrucks.com/vboard/showthread.php?t=827667)

My 66 has a healthy 250 motor, a 3 speed Saginaw, and (I believe) 4.11 gears. It really screams at highway speeds- not having a fan clutch probably has something to do with that. If I wanted to switch to a 5 speed, is a TKO or TKX overkill or a good choice in my application?

I put a TKX in my 66 ragtop and love it.

A t-5 is more than adequate unless you plan on big tourqe

agree, T5 is a good fit for your application (and more affordable) If $ not a real issue, then yes a TKO would be a nice upgrade. Here's one way to do it. Your rear end gearing is what's killin ya - other options include more highway friendly rear gearing or even a Gear Vendors o/u drive. But the trans swap would still be a nice way to go. What's your rear tire outer diameter?

So that is exactly my concern. I’ve read tons on the T5, but I’m really interested in a new piece of equipment that leaves me open for a potential engine swap in the future. All the T5 info I’ve seen looks like it involves cobbling together a tail piece from one transmission and hoping the donor guts from another are still in good shape, unless I have a major misunderstanding … since I’m a marginally qualified driveway mechanic, I wonder if I’m more likely to have success with a TK type of tranny. I like my L6, but those big V8s are seductive. Someone needs to smack some sense into me and remind me that my L6 is super cool and getting more rare because everyone else already LS swapped their trucks. I guess I’m diving back into the T5 threads ha!

No cobbling required if you start with a T-5 out of an S-10 truck. But if you have plans to go big later with a different engine combo, then yes, I would do what you're talking about and go with the TKO now. You'll enjoy it with the 6 and be all set when you get something with a little more oomph later.

You could always put a turbo on your 6 to make it more fun. I would agree that if you have plans for a bigger engine later on, do the transmission once with the beefier option

Never really considered doing a turbo… I’ve heard it’s common in Brazil with these motors though. Would love to see some setups if anyone has done this.

Powernation on Youtube did a 292 straight 6 turbo build. Looks like a lot of fun

292 build

http://www.youtube.com/watch?v=MxaRGkqrhZU

I agree with ^^^^
T5 is probably adequate and more affordable. Now, I love my TKO 500, but is damn expensive and tight to the floor/tunnel. I'm running a 292 with mods, lots of torque.

And I'm running 3:73 rear

The Sloppy Mechanics guys are having good success with a Colorado AR5 trans using an adapter. Handles decent power, cheap and plentiful.

https://www.fabbotfab.com/products/f...ission-adapter

https://cpr-manufacturing.myshopify....r5-adapter-kit

I know it's not an LS you're running, but I'm sure it can adapt to your 6.

I've got a TKO600 5 speed behind my 292 and it bolted right up. You'll want to purchase a Mid shift tower as the shifter is located to the back of the trans. I'll try and get a picture of mine installed.

Are you sure its a saginaw? I recently had my tranny rebuilt and found out its actually a Muncie 318 which is very similar. Not that it matters if you are swapping it out I guess.

Do your research before you commit to a T5 (If you want a bench seat think about shifter locations, future plans for engine power/torque). With a TKO/X there is a price jump but quite a bit more support to adapt the trans for your application. I have a TKO in my daily driver '66 and it has performed flawlessly; hands down the best money I've spent on the truck

I think it's important to really be sure what rear gearing you plan to use before investing in a high dollar tranny. Having the right shift points will make for a better driving experience. I would pull the cover off that old differential, inspect its condition and verify its ratio. Most trannys are available with different gear raitio options and what works great with a 4.11 would feel different with a 3.40 for example. What if your differential is in poor shape and in need of rebuilding? Would there perhaps be a more suitable ratio available which would be a better compliment to a given tranny? Gearing is everything to a smaller motor because iideally you can maximize its limited potential by keeping it in the "sweet spot".

Edit: From personal experience, I used to drive around with a very tall rear end and my motor would lug on inclines and I would always be downshifting and climbing hills at a higher than needed rpm. 55 to 60 mph on flat ground was 2000 RPM and my gas milage was not so good. When I had my rear diff rebuilt , I knocked it down a bit changing my 55 to 60 mph speed to around 2300. My little 283 felt like I had given it new life. It was cruising in a more appropriate range and the need for downshifting on mild grades was eliminated. Fuel mileage was improved and I had the benefits of a "peppier" truck.
However, that gear change made the first gear in my old tranny feel very short. I could easily take off in 2nd or go from 1st to 3rd with no issues. I didnt like that, and ultimately bought a new tranny which was geared to play well with my new rear gears. Now, WOW, perfect rythmic shifts and 15 mpg.