Over the years I've been slowly converting my 71 GS BBB from a street strip to a pro touring. Suspension, Brakes and Wheels are done. It was time to get into a manual gearbox with an overdrive that would still allow me extended highway travel and still be able to control the power within the range of my previously built street strip motor. A Tremec T56 Magnum, close ratio 6speed gear box was scored from a Chevelle owner whose project had to be liquidated and voila, Project "Sick Speed GS" was born. So far I have the following on order: - Billet BBB flywheel from American Powertrain -Quick Time BOP to T56 SFI bellhousing -Dual Disc McLeod RST clutch, (800 Hp) -Hydraulics for clutch -The "A body" Trans tunnel insert from "The Tin Man" I'll keep you posted on the progress. Tom
Why I chose a 6 speed Tremec T56 Magnum over the 5 speed TKO 600: -The stock T56 Magnum has a 700ft /lb torque capacity to handle the 647 hp motor. Modified magnums are handling 1200+ hp. (who knows what's in the future) -The T56 single rail internal shift system works better than the 5 speed TKO 600's 3 rail system, which has been known to hang up on a 2-3 powershift. The TKO was essentially a modified truck trans. Even a stock T56 Magnum's shifter is precise & butter smooth. -The close ratio gear set of the T56 Magnum incorporates a 2.66 first, 1.78 second, 1.31 third, 1.00 fourth .80 fifth and .63 sixth. With a 3.73 final drive and 26" tire, this spread will launch well and allow to keep the revs better within the 308S cam power band when doing some serious driving. The .80 overdrive works better on rural back roads while the .63 is more for loafing at higher speeds on interstate type roads. It's nice to have the 2 options. A close ratio 5 speed with a .63 5th overdrive would result in too much of an rpm drop for my combination at 55-60mph. - The price was right and the unit is brand new unit with 0 miles. Tom
Good luck with the pilot bearing. I had to use one that goes into the crank where the torque converter snout aligns. Dick Miller Racing sells them if you need one.
Thanks for the pilot bearing advice. I have a roller bearing and was going to hone the crank snout with a brake hone for a light interference fit. I' ll start a thread in the Pro touring section on the build
I have been researching a lot on the T56/magnums.. modified..they can handle a lot. The pftizner ones handle 1500 WHP for a year to 3000ho I recall he said.."borrowed time". These are in Vipers. I am meeting one of the Pfizner distributors for consultation next week for my build
Modern Driveline sizes the hydraulic master/Tilton 6000 TB together to work with the stock pedal ratio drilling. The combination here uses a .7" master to provide a lighter pedal with a longer travel.
The Modern Driveline supplied Tilton 6000 series hydraulic Throwout bearing with threaded flange adaptor collar for the T56 Magnum.
I have two Hurst shifter boots. A conventional size and a Super Boot. Not sure which one will locate and look the best when the Tin Man prefab cover is installed.
The shifter handle is slightly offset to the left and in the middle position of the trans, close to the factory 4Speed location. Pedals are factory bolt in style for a 68- 72 BOP A body and have been welded for strength. Although is may not be necessary, I will fab a clutch pedal stop to ensure the master cylinder piston does not bottom out and the hydraulic TB won't overtravel the actuation of the clutch fingers.
