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Joe_Rocket
05-28-2005, 02:49 PM
Any suggestions for gear ratios for best possilbe all purpose use? I'd like to be able to do some freeway cruising, too.

I'd like to compare the difference in ratios people are running with different manual transmissions, since my axle builder called and asked what gearing am I deciding on. The problem is, I haven't made my choice of tranny's yet. Thinking of going with Tyler's Kit, though...

These are the numbers I got from http://www.5speedtransmissions.com/gear_calculator.html

T56 GM (2.97, 2.07, 1.43, 1.00, 0.8, 0.62)
T56 Viper (2.66, 1.78, 1.3, 1.00, 0.74, 0.5)
TKO-600 (2.87, 1.89, 1.28, 1.00, 0.64)
TKO-600R (2.87, 1.89, 1.28, 1.00, 0.82)

Since they all have varying gearing, I'd just like to know what gears people are happy with on the street with the different trannys?

Thanks.

Blaster11
05-28-2005, 03:39 PM
I will be running 3.90's with a T56 in my 68 Bird, should be a good all around combination for what I want.

Bruce

chicane67
05-28-2005, 04:02 PM
A first gear final ratio of around 10.0 or better is for all around street driving and then you should figure the final OD from there. If you go below 10.0 its a little more work on the clutch/converter (heat) and anything over 11.0 gets to be a little too short.

E.G.-
2.87 x 3.73 = 10.7:1
2.87 x 3.90 = 11.19:1
2.87 x 4.10 = 11.76:1

2.66 x 3.73 = 9.92
2.66 x 3.90 = 10.3:1
2.66 x 4.10 = 10.9:1

And so on......... a 3.55, 3.73, 3.90 or a 4.10 would be the ratios I would consider with the transmissions noted.

USAZR1
05-28-2005, 04:43 PM
Viper T56 with 4.11 gears in the Fab 9 +
335/35/17 rear tires 26" tall = 2,000 rpm at 70mph

Joe_Rocket
05-28-2005, 11:22 PM
Great Info Chicane67! I was just wondering what final ratio I would want in first gear when I was trying out the gear ratio calculator earlier today.

Thanks...

Hurst – Scott
05-29-2005, 08:33 AM
The Tremec 5 speed TKO 600 (.64 5th gear) runs great with 3.73. The TKO 500 (.68 5th) runs better with 3.36. The TKO 500 has a lower 1st gear (3.27)

More TKO details at this site:

www.ClassicChevy5Speed.com (http://www.classicchevy5speed.com/)

Thanks, Scott

rockdogz
05-29-2005, 01:59 PM
I went with 3.70's with the TKO 600

TitoJones
05-29-2005, 07:45 PM
I usually run a 3.73 with a T56. Seems great all around gear for the setup.
Tyler

Steve68
05-30-2005, 05:16 AM
I will be running a 3:55, with a T5 or T56 I don't know which one yet,

streetk14
05-30-2005, 11:09 AM
I think that you need to figure out which transmission you are going with before you decide on a rear gear. I have an older TKO (3.27 1st, .68 overdrive) in my '68 with 3.89 gears. 1st gear is VERY low, almost too much (my 1st gear overall ratio is 12.72). Traction is non-existant in 1st. 5th gear is great on the freeway, about 2200 rpm @65 mph. But keep in mind that the rpm drop from 4th to 5th is pretty steep. I have a peaky motor, and that shift (@ about 130 mph) kills acceleration in a big way unless I have the juice flowing. I used to have 3.70's, but changed them when I rebuilt my rearend because my motor doesn't like cruising below 2000 rpm. The 3.89's also help me get closer to peak RPM in 4th at the end of the quarter mile. You need to look at your engine combination carefully. Where will it be happy? There is no sense in running a T56 with a .50 overdrive that will have you idling down the freeway when your engine doesn't like being pulled down that low. Also, if you plan on running at the strip, what kind of horsepower/ peak rpm/ trap speeds do you expect? I know that these decisions are never easy, I've spent too many hours brainstorming these things. Good luck, let us know if we can help. By the way, check out www.smokemup.com . They have a really good gear ratio chart that will compare 2 different ratios. Ok, I have to go drive my car now
:drive: -Andy

parsonsj
05-31-2005, 06:37 AM
Exactly: you gotta factor in your engine's "happy" rpm. Two other things to consider are rear tire diameter (a shorter tire will act like it has more gear), and overall torque produced by your engine.

In my case, I'm expecting 500 to 550 lb-ft of torque from my 427, and I'm running short (25.375") tires, so I'm using a 3.25 gear with my TKO-600R (2.87 first gear, .82 5th). That puts me around 9.4 overall torque multiplication in first with lots of torque from the engine and short tires. It will have me cruising at 70 mph around 2300 rpm which should be about right for my engine.

jp

Joe_Rocket
05-31-2005, 04:29 PM
Thanks for all the input.

I chose a 3.73 rear gear. That gives me a a 10.7 final with the TKO600, an 11.1 with the T56, and a 9.9 with the Viper T56.


I will probably go with a T56 if the money is there after my little side project pays off.

Waiting for someone to do a T56 group purchase....

CAMAROBOY69
06-01-2005, 03:31 AM
I have run the car on the track(Gingerman Raceway), the local dragstrip, 2004 Power Tour and several other events.

I have the T-56 2.66 first gear and .50 6th gear.
I am running 4.11 gears in the rear and I wouldnt change a thing. I really think my car is set up perfect for a 400hp first gen Camaro.
2,000rpm @ 75mph

I guess if the 4.11 scares you then the next best thing would be 3.73 but I dont have any complaints with the 4.11. Keep in mind I only have about 400hp though.

69speed
06-01-2005, 07:39 AM
I'm running 3.89s in my 9"ford behind a T56. Love it! I'm sure 4.11s are good too, but I don't stay in first long as it is. I wouldn't change a thing. It runs 2100rpm at 80mph in 6th (295/40/18s on the back)

JayBird
06-02-2005, 04:16 AM
I have the TKO-600 with 3.73's. It seems to be the correct ratios for my 350 sbc with 470hp.