I am looking to upgrade the tranny in my 69 convertible and I would like to hear from people on their experiences with either the 5 or 6 speed conversion. I am about to finish up my suspension upgrade and I would like to do the tranny before I get the car painted.

What are the pros and cons of each?

I am currently running a small block Fast Burn 385, 4-spd.

Thanks, Eric.

 

ask this again in one month and Ill have an answner for you.
sorry It could be sooner
EDIT: I just called Kessler. unfortunally my tranny will not take 6 to 8 weeks, Instead it will take 12 WEEKS! aarrg. well I may get the carpanted before it arrives


[Modified by 71'AirStrike, 10:59 PM 11/4/2003]

 

Come on people, the weekend is over!
And I know that some of you are running this setup.


[Modified by EricU, 9:49 AM 11/3/2003]

 

It's so new, I doubt if anyone has been able to do a comparison. I've had mine on order for more than a month, so I wasn't even aware that they had a new kit for Vettes. It looks like a totally different transmission, based on the 650hp rated unit.

In my opinion:
Pros - 6 speeds, higher power rating
Cons - higher price, higher first gear, requres slight modification to crossmember

I'll probably stick with my original unit (it's due in two weeks), but I would have given real strong consideration to the six speed if I would have known about it this summer.

Good luck -

 

Eric, the 6 speed requires modifications to your cars transmission tunnel. It isa bigger tranny. I don't know what the mods are. I finally completed my 5 speed installation last Friday. With the .68 OD, your car will fly down the road. You can install this tranny with no mods to your car or crossmember. If you still have the exhaust hanger at the crossover member, this requires some modification. Other than that, just follow thier directions and you can get it in. If I were to do it again, I think I would wait to put the fluid in the tranny until I have it installed. This would be a change from thier directions.

 

Thanks for the comments, I knew someone had to have a 5 or 6 speed from Keisler!

Eric.

 

I would also consider my rear gears. If you will look closely the 5 speed has a much lower first than the 6 speed. (I know that the 475hp kit on the website has roughly the same first gear, but as of a month ago it was not available.) If I had a numerically low rear end, 3.08, 3.23, 3.55 I would use the s 5 speed because the .67 would be enough od. But if I had a tall rear gear 3.73, 4.11, 4.30 (some people will run a3.73, but keisler's web site calculates that a 3.73 would accelerate like a 4.84 in a standard 4 speed.) I would run the six speed. This was not a consideration for me because my rear end was shot so I could pick what rear gears I wanted

Another important consideration is horse power, if you plan to exceed 475 hp then the 650 horse 5 speed only has a 17 percent od which doesn't justify the expense of the swap. So If youwere planning to go with over 475 horses. I would lean toward the 6 speed.

If you have a numbers matching car another consideration is originality if you go with the 5 speed kit you can go back to stock anytime you wish, but with the 6 speed kit, you must cut the front lip on the tranny tunnel, and I believe elongate the hole in the floor very slightly. I went to keisler's and saw the installation on a 79, which I was told by one of keisler's mechanics has a smaller tranny tunnel than my 74 which I would assume is the same as your 69, but I don't know for sure.

I would also like to suggest one other idea. It is not on the website yet but mine is being built as we speak, I will be getting a 650 horse kit with a .8 5th and a .62 6th. I realize that sounds insane at first, but at some point I plan to run over 600 hp so I needed more than the 475 hp kit. I also like carbs and agressive cam profiles which means my motor will not make most of its power down low in that 1500 rpm area. I know the fastburn makes more torque than my 350 , but I still believe it will be in a bind trying to push your 3200 pound car down the freeway at 2500 rpm at 98 mph, or 137 at 3500 (with 27" tires and 4.11 rear http://www.keislerauto.com/gm/transm...68-82_6spd.asp ). I had a th 400 in the car before and got much better gas milage at 70mph/2800rpm than at 40/1800. But to be honest the biggest reason is the car is more fun to drive the longer you keep it in the rpm band.

I would also like to encourage you to call Keisler and get a few numbers of satisfied customers. I did this and it made me feel much better about the money I was about to spend.

I hope this has been helpful. I am sorry it is so long. Email me any questions, I have been sick and am bored out of my mind so it's no trouble,

 

Well I think I pretty much decided on the 475 hp 5-spd, I like the ratios and I am just looking for an extra gear.

It should do fine behind my FastBurn as the future plans call for a bit more aggressive cam on a tighter lobe center and EFI. I would be happy with 450 hp at the crank. Of course I will never really know as the car will be chassis dynoed, and I am not pulling that engine out again! (Hopefully!).

Thanks for the suggestions,

Eric.


[Modified by EricU, 10:41 PM 11/3/2003]

 

The 5 speed is a great unit. I installed a Tremec 3550 (same as a TKO but rated at 425 ft-lbs vice 525 ft-lbs) almost two years (and 6000 miles) ago. With the 3.36 rears, I can roast them at will in 1st and cruise at 2000 rpm at 70mph in 5th. :D

I bought my transmission from Mike Forte in MA. He mods the Tremec for the GM application and the only mod I had to do was the shifter.

Tremec:
Modded :
For a handle, I just had the shop that welded the shifter up cut my old Hurst down in size and redrilled it for new bolts.

I used a mount from BowTie Overdrives that looks just like the one Keisler sells and had a driveshaft made locally. The only reservation I have about the Keisler setup is that it seems to have a one piece yoke at the tranny and I will say from experience that it is a lot easier to install the drive shaft if the yoke comes apart at the tranny.


FYI. My total cost was about $2200 for the equivalent of the Keisler kit. The Keisler setup wasn't available back then but looks pretty nice if you want it all in one piece.


[Modified by SteveG75, 11:19 PM 11/3/2003]

 

HP is a factor, but these units are pretty stout. After speaking with Keisler, I found out that they are rated in the highest gear. A 475hp tranny could handle much more than that in 1st - ditto for the 650hp unit.

 

So which TKO does the keisler 5 spd have the 1 or the 2?? I sounds like a good kit I may have to get eventually.

 

Yes.


:D Both but as stated the TKOII only offers a .8x overdrive, hardly worth switching from a muncie for.

 

thanks for the info! :cool:

 

I'm running a 383 with the tremec trans and it's by far the best money spent on the car. It's got over 15k miles on it and no problems. I can spin the tires thru 3 gears and still knock down 17mpg when cruising to the keys or daytona beach. Life is good. :)