Hello all. This is the question. Is there a six speed that will stand up to 600 ft/lbs of torque. It will be ran had so I need to know. Or should I go with a wide ratio 4 speed (m22) and low numbered gears. Any thoughts.
Motor is 427 bbc 550 horse and 600 lbs/ft. Nine inch rear.

 

About your only option with anything other than a Lenko is the Tremec TKO. 525 lb-ft. I just put one in this weekend ... it was awesome.

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355 c.i.
Dart 180 Heads
Lunati 224/224 cam
Harland Sharp 1.5 rockers
Performer RPM Manifold
Holley 600 cfm double pumper
Hooker Super Competition Headers
Flowmaster Exhaust
Competition Engineering Sub-frame connectors
Tremec TKO
Pro 5.0 Shifter
GM posi 3.42 rear
Hurst Roll Control
13.9@102

 

you might go with a richmond overdrive. They have 5 and 6 speeds that can handle that level of power.

 

richmond od is not rated at 600 ft lbs. also I dount an m22 is stronger than a t-56.

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1991 Firebird
350 L98 (was a 305 TBI),T-5,Edelbrock TES and cat back,Accel manifold
NOS,subframes,jegster torque arm,MSD Digital 6
AFPR,Lakewood lcas
Hurst linelock,SLP cam (206 212 .480 .486),relocated battery,cold air,Hypertech chip,centerforce df,clutch
poly bushings and mounts
AFR 190s
Harland sharp 1.5 rockers
autopower rollbar

12.33 @ 114.83 juiced uncorrected

13.510 @ 102 non juiced uncorrected

 

TPI Guy,
Did have to change the yoke on the driveshaft? How did the crossmember line up?

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'91 Formula
383CI Superram, Sportman II's
SLP Cam 214/224 .470/.490
Vortech V1 S-Trim with custom 8 rib pullies
5-speed
3.42
12.34@117.04, 1.91 60Ft.
on Drag Radials

 

Well, I'll tell you, I have a 1973 Nova, so my experience isn't going to apply a whole lot to the f bodies. What I can tell you is that Ed1LE put the TKO in his car, and he said it was pretty sraight forward. For me, it was easy because I have a standard (non t-5) GM bellhousing. Mike Forte (www.fortesparts.com) makes an f-body tko that takes into account the t-5 bellhousing rotation. I had to buy a special offset crossmember for my application. Here's a bit of trivia for those of you playing the home version of the game. Most of the suspension parts from first gen camaros and firebirds and the 68-74 nova's (x-bodies)interchange, so I bought that x-member. The TKO has a Ford output shaft, 31 spline, and Forte's includes it in the initial price.

I gotta tell you though, the most beautiful part of the whole ordeal was when I put the pro 5.0 on top and shifted it the first time. It's got short throws and this offset shift mechanism ... I'm in love.

 

You might want to check out a topic "ZF-6 v. T56 that is on the second page. One guy claims to have put a T56 behind a "9xx horsepower" beast.

 

I agree with Parrydise 7 I know for a fact that the T-56 is extremely under rated. I was reading about the corvette Tiger shark and I think it had very similar and it held! It had I belive 600. I don't know if that was just GM being cheap but you know they test them and it held. My friend has one with 55o to it and has had no probs.

 

Do some looking at a viper T56
I wanted to put one in my 89 but I finnaly settled on a 4th gen.

A couple of notes on the Viper box

shaft is 1-1/8" diameter, 26 spline

the total visible shaft length is 8", the portion that extends past the plane of the
rear bellhousing surface is 7.25".

The viper bellhousing is 5" 'deep'.

 

M22's are overrated; case flex is why. Also, M22s aren't wide ratio.

You're best off with a Richmond 6 speed.

Just because a tranny is rated at 500lb-ft doesn't mean it won't hang with 600. Get a GOOD shifter (the Richmonds come w/ a Long shifter; that thing kicks butt.) and learn how to shift and you'll be fine.

 

t-56 is the way to go, it will easily hold 600hp as long as you dont power shift, but it is just like any tranny, beaten hard enough and it will break.

On Camaroz28.com there is a guy by the name of romanSS who has a 9.xx second 427 stroked LS1 with 250hp direct nitrous fogger kit. with the stock tranny and ram racing clutch,

but he says he is on the limit, and is getting the internals cryo'd

 

Tremec T-56 specific model #AA08-000-013 is rated for 650 ft-lbs.

If anybody wants to argue that look on Tremec's website and read the specs.
http://www.ttcautomotive.com/products/T-56.asp#Car

Bummer is it's a close ratio box, not the wide ratio that people think of when you say T-56.

PN# TUET1806 is a wide ratio box rated for 550 ft-lbs, actually uses the exact ratios the 4th gens have.

The aftermarket box that everybody complains is weaker than the stock box that handles 450 is rated for the same amount (450)

 

Don't leave out Jerrico Transmissions...
These are race proven to handle gobbs of torque...
A lot of circle track racing including Winston Cup uses it.

Get ready to fork out some big bucks for any one of these race built transmissions.

Ron