[frankyboy455]

I'm preparing to convert my son's 68 Sprint 'Bird from a column shifted 2 speed automatic to a 4 speed on the floor.

Here's the plan so far and what parts I have acquired:

Use a 1975 Borg Warner Super T10 I already have. My shifter set-up is one I previously modified to fit in a first gen firebird original 4 speed hole, works with factory console, tried it before.

I bought a used OHC6 flywheel and bellhousing from a cammer guy on firstgenfirebird.

I have the correct clutch fork, GM part number: 9787069

Now for the questions: Which clutch and which clutch release bearing do I need ? I know I need a 26 spline clutch disc since the BW super T10 has a fine spline input shaft, but otherwise ?

I believe there are two clutch sizes available ? 10.5" and 11" ?

Also, I have read somewhere that a 6 cyl flywheel is "stepped", mine does not look stepped, it seems flat.

[camerjeff]

It is a 10.5" Clutch, I have never seen a stepped flywheel on an OHC-6. If you are interested I have a New Hayes Clutch pressure Plate and Throw out bearing I was going to use with a Muncie M-20 with the fine spline input shaft so it is a 26 spline clutch plate. It was installed in the car, but the engine was never started, Currently still bolted to the OHC-6 that came out of my old 67 Lemans. I will sell it for 1/2 of the current new price from summit. Let me know if interested and I will get some pic;s this weekend.

[frankyboy455]

Do I understand you don't need to search for a specific application ? Like there are four different applications: 11" or 10.5", and 10 or 26 splines ? That makes sense, but what about the "right" throwout bearing, how does one figure out which one he needs ?

[Jeff Hamlin]

FWIW;
Everything borrowed/matched to the GTO standard app/spec 10.5 (10.40)
HD app was/is 11" you don't need this.

I would consider the original FW as stepped.
I think it was nothing more then to save on some machining?,
Once had one machined and they cut it flat I experienced no issues from this.

[Goatracer1]

Your ST10's first gear is high for a 6 cyl. The original trans has a first gear in the 3.'s But if thats what you have.....

['ol Pinion head]

Originally Posted by Goatracer1

Your ST10's first gear is high for a 6 cyl. The original trans has a first gear in the 3.'s But if thats what you have.....

Agree, forced to install a 2nd design T10 behind a OHC-6, I'd consider the 3.42 1st gear ratio 2nd design T10 out of an '81 305 4spd T/A or Z28. Using an oem '68 or '69 Bird Hurst 4 spd shifter, going to face some real challenges adapting the shifter to the different spread mtg bosses of the late T10.

[vetty]

Why not put a t5 in it? You are converting from auto so you have to cut the floor for the shifter anyway. Very straight forward and parts can be found cheap and easily. Seems like a no brainer, but thats just me...

Running a t5 with 4.11 gears and still runs about 1800rpm at 60mph. What else can you want lol?

[frankyboy455]

Originally Posted by vetty

Why not put a t5 in it? You are converting from auto so you have to cut the floor for the shifter anyway. Very straight forward and parts can be found cheap and easily. Seems like a no brainer, but thats just me...

Running a t5 with 4.11 gears and still runs about 1800rpm at 60mph. What else can you want lol?

Hey Vetty, I know this is a good idea but having the shifter in the wrong spot really bugs me. What is your combo of parts, source of T5, etc ?

[frankyboy455]

Almost done with the conversion !

[Jeff Hamlin]

Looks good,
Always like the no nonsense look of console-less interior.

[frankyboy455]

Originally Posted by Jeff Hamlin

Looks good,
Always like the no nonsense look of console-less interior.

I love it as well. My son's inspiration to go console-less came from my 68 Camaro.