SapphireHawk

Has anyone ever changed their 5th and 6th gear ratio to accomidate 4.10s in the back? I'd like to quicked up 1 through 4 but I love the MPG I get in 5th & 6th with the 3.42s. Not to mention crusing at 90mph in 6th gear at 2,000 RPMs is pimp.

Is it possible to make 5th Gear like .65 and 6th Gear .42?
Does anyone cut custom gears?
Would you need a custom counter shaft also?

kossuth

iTrader: (12)

Hmm, they don't make gears like that. If you really want the 3.42 feel back here is what you can research into. The 93 T56 uses ratios like this
1st 2.97:1
2nd 1.94:1
3rd 1.35:1
4th 1:1
5th .84:1
6th .62:1

With that idea in mind here is what you have to consider about the T56. The 1-3 gear countershaft is separate from the 5-6 countershaft on these things. If you really really want to go through the trouble you can buy 1-3 gears for a 93 T56 with all the syncro assemblies and just throw 3.73's or 3.42's back in the rear. Probiably would make the rearend stronger also. Problem with this idea is I have no idea if the 93 T56 1-3 countershaft will mate to a 5-6 countershaft being if you have taken on apart before you are aware that the 5-6 shaft just drops into a groove on the 1-3 shaft. Hope this has the wheels turning alittle.

SapphireHawk

Yeah I also had looked into this idea. They refer to the 2.97/1.94/1.35 as wide ratio and the 2.66/1.78/1.30 as close ratio. I was figuring it would just be cheaper to replace 2 gears as opposed to 3. Since I have never seen a wide ratio version I am not sure if they are the same, but they might be.

Would this make gears 1-3 stronger also?

kossuth

iTrader: (12)

Not really. I know the 93 T56 is only rated to 400 ft lbs of torque while the 94+ is rated to 450. Not sure of what made it different. Another thing I just throught of that may or maynot kill this idea is do the 94 and 93 LT1 T56 trannies use the same input shafts, being I think the countershaft drive gear is part of the input shaft? Reason I'm saying this is that something has to drive the countershaft and if the gear on the input shaft doesn't match the gear on the countershaft then this idea would be shot. If the input shaft is the same from 93-94 then you are good and you can have a reasonable amount of certainity that the LS1 input shaft would work with a 93 countershaft. Now the question about the 5-6 shaft mating to the 1-3 shaft is a whole nother matter.

calhoon

iTrader: (6)

You kinda touched on it a bit. All ratios in the box are set by the input"headset" ratio. The 2.97 has a different headset than the 2.66( as well as other gears) To just swap the 5th & 6th meshes won't get you what you want. Std 2.97 has a .80/.62 5th/6th set.aA std 266 has a .74/.50 set. A2.97 set in a 2.66 box gets .84/.57. A 2.66 set in a 2.97 box gets a .83/.502. Bottom line - there are no gears made for the .65/.42 set you seek.

SS2win

iTrader: (11)

Check out this article

http://chevyhiperformance.com/techar...48_0405_trans/

the guys there went the other way with the overdrive gears cutting a .80 and .64 but perhaps they could steer you in the right direction... damn man aint a .50 enough?

ChevyWeatherman

iTrader: (2)

According to my calculations, 90 MPH in 6th with 4.10s is ~2400 RPM...live with it.

SapphireHawk

Thanks for the link, it exactly what i was lookin for.
Just tossin around the idea, but since it is possible, I wonder what gear 5/6 gear ratios i'd need for 4.30s.
I'm always tryin to be different and cause trouble.

calhoon

iTrader: (6)

The article is somewhat flawed - there is no 25Tooth input( its a 26tooth - like the Fcar but a different pilot) This is a Viper based T56 (same 1-4 ratios as an F-CAR) with the OD gears from an Aston Martin DB7/T56. It requires a 30T output and associated changes to work.Also the shifter is in a different location( further forward)

ls1 1990 VN

contact Mal Wood in aussie.
www.malwoodauto.com.au
e-mail: malwood@flexi.net.au
He does a close ratio 5th & 6th for the commodore t56. If you have all details about yours he may be able to help.