I have a 70 Vette with 3.36 rear gears/350 ci engine (430 HP) and I have been talking to Keisler and Classic Chevy about which TKO to purchase (500 (.68) or 600 (.64)). One company recommends the TKO 600 (.64), since I have 3.36 rear gears and I would have to shift out of first gear to quickly in the TKO 500 (.68) model. The other company says I would be fine with the TKO 500 (.68). I assume that all the transmission gear ratio's in the Keisler TKO 500 (.68) and Classic Chevy TKO 500 (.68) are the same and also the ones in the TKO 600's (.64) are too.

Does anyone have this rear gear setup (3.36) and a TKO transmission? If so, which TKO would you recommend?


Also, does anyone have the Keisler hydraulic clutch setup in their TKO? If so, was it worth the cost? Classic Chevy doesn't recommend this, due to the Vette firewall being fiberglass and they say it can flex when pushing in the clutch. Is this an accurate statement or just a sales pitch? The manual clutch setup makes my leg tired, since I'm in the city a lot, so a hydraulic setup would be nice.

Thanks in advance for the help guys.
C.J.

 

Its been a while since I have driven mine but I have the same setup you are describing in my 70. 3.36 with an older Keisler kit. In my opinion it works great. You get out of the hole quickly and get the mileage on top. As far as the clutch is concerned, I am still running manual clutch linkage. Can't help you on that one.

 

get the 600 with the .82 od Modern clutchs don't require very much petal effort.

3.36 X .82 = 2.755

 

I cant give you a good answer on the trans gearing but I got the .64. Since you are shopping for quotes on 5 speed kits you should check out vettesbydesign on this forum. I just got my TKO from him today and will have the rest of the parts shortly and post up some pics. He was easy to deal with and prompt shipping everything out. Prices are good too.

 

If you have a 430 hp 350 ci small block you don't really have the TQ to use a .68 or .64 OD

 

Eddie70,
I see that you are satisfied with your TKO and I was wondering if you have the 500 or 600 model? Thanks.

C.J.

 

Bahamasair,
Please let me know how your install goes and if you had to do any mods. If the price is right and the install goes fairly smooth, I'll check into getting my TKo from VettesByDesign.

C.J.

 

Are those numbers correct? I know the 600 has a .64 fifth gear. I thought the 500 had a .82. Anyway, I put the 600 with the 2.8 first gear and .64 fifth gear in an early Camaro with 3.42 rear end. So, similar to your situation. The first gear, and the spacing in the first four gears are ideal. The 3.2 first gear in the 500 would be way too low. However, the .64 fifth gear is too high. I'm turning only 1,900-2,000 rpm on the freeway at around 70 mph. Something closer to 2,400 rpm would be more ideal. In other words, the optimum cruising speed is more like 85 mph, which doesn't work for the boys in blue around here.

 

LB66383,
Thanks for the input. Below is a link to the gear specs from Classic Chevy's website for reference.

http://www.classicchevy5speed.com/De...it-Tremec.aspx

C.J.

 

I have a 430 hp small block. It has good torque. I have 3:36 gearing and have selected the TKO 660 RR tans for the 5th gear reduction of 18 percent. The TKO 600 gives the 3:36 rear gear a effective multiplyer of a 3:82 rear gearin first.
I can fry my tires at will with the 3:36 and the 3:82 effective first gear will be only more grins. The 18% over drive of the TKO RR drops 70 mph rpm's from 3,000 to 2,400. Perfect.
The TKO 500 gives a 3:36 rear car a first gear rate of 4:30 or so. Dumb, less you got a 250 hp motor.
Do the math, you know your car: what ratio do want for first gear acceleration and what rpm's do you want to run at your cruising mph.
Both Kiesler and Classic Chevy have calculators on their websites.

Daffy

 

The 500 has a 3.27 first gear and the 600 has a 2.87 1st gear. The 600 can be had with either a .82 or a .64 OD. So all 3 transmissions have different gearing. With 3.36 gears I would stay with the 600 with a .82 OD. I have a .68 OD with 3.70 gears and 5th gear is not used until about 55 mph. I also had a 350 with about 420 HP before this motor and I ran a .68 OD with a 3.70 gear and it worked well but 5th was useless below 50 mph. With 3.36 gears you would have to be doing 70+ to really use 5th with a .68 or .64 OD. Keisler list all the ratios on their website.

 

What is the theory behind this ? A car driving at say 75 mph doesn't need the total torque of the engine to keep it going just a fraction.
Difference is top speed in fifth. It will probably not reacht maximum in fifth but that is seldomly used in normal use.

 

I have a 3.36:1 diff, and the TKO600RR (0.82 OD) with the McLeod internal Hydraulic throwout bearing.

Motor is a healthy 383.... rated at 475hp / 460ftlb

In my case, with the 3.36 diff, I wanted to be sure the motor was spinning in a sweet spot whilst cruising rather than lugging.

I have a 242/240 @0.050 roller cam which doesn't really like sitting below 1800 rpm. 2300rpm @ 70mph suits me fine.

Gear shifts are light and precise, clutch is a pleasure to use, and the gearing is spot on to take advantage of strong midrange and upper rpm power.

I would consider the best option is to have a 3.70:1 diff ratio with the TKO600 (0.64 OD)

Ideal for performance and still maintains good highway cruising rpm.

Another club member has a 3.36 diff with the TKO600 and the 0.64 OD and is very happy too. He does a lot of country interstate touring, and loves the quiet ride and improved fuel economy. He has a stock 350 though, and motor is happy to choof along at 1600~1700 rpm.

In regards to clutch / firewall flex.... I have a right hand drive vette, and the biggest hassle I had was having to fabricate a RHD clutch pedal mounting with proper alignment for the master cylinder rod travel.

To minimise movement, I added a cross brace which secures the clutch pedal mount to the steering column mount assembly.
Also had to use plastibond to fill up the gap between the plate and the inside contour of the firewall.

It works well, but was the most time consuming part of the conversion.



I did spring a leak at the MC after the first week due to the clutch rod NOT being aligned well enough with the MC bore.
I then machined an aluminium tapered bracket to add 5* slope to the MC. No problems since.



cheers
tom

 

5th gear is all about highway driving an fuel economy for me. I have the TKO 600 with .64 OD with a 3.08 rear end.

80 mph on the highway is less than 2000 RPM's and I love it. I do have over 450ft/lbs of torque at 2000 RPM though. You need some torque to pull the 5th gear. If it were my old 355ci I would not even be able to shift it into 5th

 

MotorHead,

My motor specs say I have 425 lbs. of torque. Do you think this is enough torque to turn the .64 OD? The link below takes you to the motor.

http://www.enginefactory.com/350_430hp.htm

Thanks,
C.J.

 

I have the TK0-500 and 3:36 gears and about the same hp as you. Mine comes out of the hole like a jackrabbit and the rev's come up real quick. I would never run a rear gear any lower than a 3:36 otherwise 1st gear would be useless.
At 70 mine does about 1800 if I remember right, the OD is useless at under 55mph.

 

At 70 mph with your 3.36 you will be at 2000RPM approx. with the .64 overdrive. The torque at this RPM to the wheels would be around 200 maybe a bit more. Your peak TQ to the wheels might be 325 but at a much higher RPM.

Mine puts out 360ft/lbs at 2000RPM to the wheels so I would say you might not be having any fun with 3.36 rear and .64 OD Could be wrong on this but I personally could see a problem if my torque was any lower, it would just start to lug along

YOu really need big torque or higher gears

 

In street driving I can go into 5th at about 45....and cruise around essentially idling...on the freeway I get into 5th around 50-55 as described above...but theres not much grunt at this point...if i had to pass someone I better be going 70 to start with or downshift

3:70 rears TKO .68 OD...

But I can get stellar gas mileage just bopping down the freeway.. and in 1st gear I could climb a telephone pole

 

Will do bud.

 

I think Gkull is pointing out that a 430hp 350 is quite stout, but probably will not have as much torque below 2000 rpm as a stocky.
Your 430 lb-ft of torque is most likely at about 4500 rpm.
Although the engine will chug along and maintain highway speeds at 1800 rpm, it will not be comfortable in accellerating for overtaking slower traffic if left in 5th... a down change might be necessary.

Like I said previously, with a stock 350, 3.36 diff and 0.64 OD one of my mates has no issues. But a performance engine may not be as comfortable chugging along at 1800rpm.

I also had a lot of issues with my Edelbrock carb supplied by enginefactory on my 383. Could NOT get it to run right, even with a lot of time spent on the dyno to sort it out. I've now put on a Holley double pumper, and the off idle hesitation, and issues with part throttle below 2000 rpm are solved. Longer term plan is for multipoint fuel injection with computerised ignition/fuel maps, which would do wonders for optimising torque even at lower rpm