66 Vette

I am considering a transmission upgrade from my current four speed to either a 5 or 6 speed. My 66 has the original 327 engine 300 hp build up to approximately 350 hp. I am running 4.11 rear gears. Keisler is recommending their RS 400 transmission, Hurst Driveline is recommending their TKO 600 since I am running 4.11. Hurst is recommending their TKO 500 only if I was running 3.04 or 3.36 gears. There is quite a price difference between the Keisler and Hurst. I have asked for a quote from Tremec but they have ignored my request for the last two weeks. What recommendations does this forum have based on those that have upgraded to either of these transmissions? I appreciate your input to allow me to make the correct decision.

Crunch527

I had a TKO600 with 4:11 gears and it was a really nice setup. The car ran great and had great driveability. With the TKO600s there are two diffferent overdrives to pick .64 or .82. I had the .64 version as the .82 ratio is a lower overdrive with higher 5th gear RPMs.

The TKO500 has different gearing and is better suited for the low HP cars with taller gears.

I went with Kiesler last time and I am considering their RS600 this time.

What are the specific price differences between Kiesler and Hurst...I have never used Hurst.

Hope this helps.

Frank

Tampa Jerry

I also have a 66 with an L-79 with a 4:11 rear. I replaced my M-21 with a Tremec 600. First gear is really steep and I can almost "walk" the car in first. That said, the rpm at 70 is about 2400. Much better than 3800 without the overdrive. I purchased my gearbox from Hurst in CA. Good price and good service. Jerry

66 Vette

Difference in price approximately $1,000.

SLWRNU

Just put a TKO 600 in my 65 L79 with 3:70 gear. Along with the Gen IV Vintage Air this is the best mod you can make. 2100 RPM at 70MPH what's not to like.

66 Vette

Tampa Jerry, what do you mean "walk the car"? Both Tampa Jerry and SLWRNU did you purchase the kit and did the kit come complete for a easy drop-in or did you have to modify and purchase additional parts to make the transition for example a clutch disc? What if any issues did you have installing the 6 speed and who did you purchase your kits from?

Bluestripe67

"Walk the car" refers to the ability to let the clutch out and the car will travel on it's own at idle; no need to touch the gas. This is very common on vintage 4WD vehicles, especially Jeeps. Your could actually get out of the vehicle and "walk the car" Dennis

Dan Hampton

I think he means that at 4,000 rpms in 1st gear he can walk as fast as the car will go in that gear--sort of.

Crunch527

Are you saying Hurst is cheaper?

66 Vette

The RS400 is less expensive, it is supposed to be a drop in without having to change clutch disc etc.; at least that is what I am understanding at this time.

66 Vette

I mistakingly said 6 speed, so far I am only discussing 5 speeds from the distributors since that is what I have quotes for. RS400. TKO 500 and TKO 600.

Tampa Jerry

I bought the TKO 600 and the install kit. It included the gearbox, speedo cable, rear mount, driveshaft and pilot bearing. There is no linkage to speak of, it shifts via rails inside the transmission. I had to add the shifter handle and transmission fluid. I also bought hockey pucks and used them as spacers between the crossmember and the floor of the car. There are lots of posts about floor sagging and Tremec transmissions. You can use your own bellhousing, clutch, flywheel and throwout bearing. You will have to dial in your bellhousing to determine if you need offset dowel pins. Most do not. The install is tight. There was a lot of cursing at my house that day. But, all in all, the install went without a hitch. As far as walking the car, the first gear on an M21 is 2:20, the first gear on the Tremec 600 is 3:20. Couple that with a 4:11 and you have to try hard to stall the engine. You can almost sidestep the clutch at idle without stalling the engine. It would be nice if Tremec would have an option to allow selection of the gear ratios. First gear is almost useless. Jerry

Crunch527

Ditto the "lots of cussing"....I bought the "bolt-in" hydraulic clutch option too...sounded like a good idea but it leaked

I was also converting from an auto and the pedals were a blast to install as well.

Overall, the install I did isn't that bad but don't let the sales folks tell you it's easy. I like laying on the garage floor. Dialing in the bell housing is a challenge if you don't pull the engine. Since the crossmember on my 73 unbolted, I left the engine in the car AND I had to change the bellhousing alignment dowells...what a pain the azz.

The crossmember in your 66 is welded in place unless you have modified to bolt-in. The welded crossmembers make for a tight fit and you will have to fight getting the trans in place with the engine still in the car. I talked with Hurst about the welded crossmembers today and they recommended pulling both engine and old trans. Setup bellhousing and clutch with engine out of the car, slide trans into place and push as far back as it will go, then reinstall engine and mate the trans. Sounds easy enough...but I still think it may be possible to mate the engine and trans (out of the car) and install them as a unit.

Not trying to scare you off but I dont care what "bolt in kit" you buy there is always some "cuss-n-fit" (custom fit) required.

Cheers,

Frank

KeislerSales

Opinions vary greatly, especially when it comes to cars. The rule of thumb is always go with the 600 series when a 4.10 rear axle ratio is involved.

Personally, with a 327 that doesn't have much low end grunt and likes to sing, I like the lower first gear for a better launch.

In the end it's you that you have to satisfy so do your homework and figure out what works best for you. I can run through lots of different rpm/mph scenarios with you so call me if you need further help.

SLWRNU

Bought the entire kit for the TKO 600. Includes new clutch disc, driveshaft, factory looking shifter, and all necessary parts. Did not pull the engine. Bellhousing is installed on the trans and then trans lifted over the crossmember and then slid forward. Don't get me wrong. Installation takes some finagling but job was completed in one day.
Love driving the car now.
Giid luck.

OCS1667

I can't believe nobody address the T-5 transmission GM built for about 10 years for the Camero and Trans-am. I couldn't be happier with the trans. It's been installed for about 4 years with about 6000 miles on it. I get about 21mpg on the Highway @ 75 mph at about 2300 rpms. My engine is the L79, 350 rear end.

Cost's are $3-500.00 plus install prox $500. for the trans. I've talked to several Cobra an a Ponez owners and all are running the trans. with no problems they say. The trans is very smooth when shifting and mine has no discernible noises.

If you have any questions about the install or trans PM with your PH # and I'll call you.
Dennis

66 Vette

I have listened to all of you and have gone on various GM car sites to gather as much information as possible before I made my decision today. Every site I went to mentioned the difficulty of installing the TKO due to tunnel clearance issues, plus the 2nd to 3rd shifts. I ordered a Keisler RS 600 this morning based on this input and information. I hope the wait is worth it and look forward to receiving the RS 600 Transmission kit as soon as it is available.
I thank all of you for your input.

mattowen

Hey 66.... did you get the RS600 yet?

If so... what are your first impressions?

If not... how long did they say you have to wait?

66 Vette

Have not received the transmission yet; I was advised when I ordered it would be 5 months. Latest update on when I will receive it is not good, probably middle to end of next year. Hoping they will improve on that date and meet the original promise date.

KeislerSales

That's incorrect. Who told you that?