Nathaninwa

HI guys, workin on a T56 for my project car to replace the T5. Im picking up a rebuild kit and also looking at a 30 spline output shaft. I see that Rockland has a fully splined shaft that allows for 5th and 6th gear changes. Will this work in the GTO? Can I change out the drive/driven and get the .8/.62 overdrives with the 30 spline shaft?

Ive asked around, and I get mixed awsners on the subject.

jmd

iTrader: (4)

No, but you could easily by keeping the GTO mainshaft and changing some parts to 93 f-body. But, you'd be going from double cone to single cone synchros.

Nathaninwa

That would that just be single cone syncros in 5th and 6th? Ill have to relook at the rpm calcualtor.

This is going into a turbo 4 cylinder application where I cruise rpm neeeds to be in the 2200 to 2300rpm around 75mph. Anyless than that with the cams/setup I have I start to build boost from the load and the mileage gos all to hell

I have a 3.73 rearend right now with a .73 T5 transmission. Cruise is good at around 2800 at 75mph. But Im looking to get the strength of the T56 and retain the cruise. So the .8 and .62 would do me good with the new 4.11 rearend Ill be installing.

So Im hoping to install the larger mainshaft and do the gearing. Currenlty I dyno at 421wtq/501whp. Im upgrading some things and looking to tune on E85 and be alot closer to 550-600 rwtq and 600-650rwhp. The car has launch control and no lift to shift, and antilag if i want. Its mostly a daily but does see track time.

Nathaninwa

I figured I would bump this. After talking to several companys and the GTO trans running the Corvette gearing, there is just no way that anyone could sell me the different gearing. After talking to Rockland (RSG) there able to help me out with the T56 magnum. They can give me just about any overdrive .8/.74 for fifth and .63/.5 for sixth. So Im getting one with .74 and .63 and should dial my car in just right.