Converting to a 4-speed

[deucephaeton]

My son is the Jetfire owner and we are converting his car to a 4-speed. We bought all the parts we needed for the driveline from a guy parting a 4-speed Cutlass. Now comes my question. The trans tunnel on the 4-speed Cutlass is different that the trans tunnel on our Automatic. The 4 speed is bigger. It appears the factory put a larger tunnel in and cut the old out. The 4-speed tunnel was spot welded to the old and the original was cut rather crudely and seam sealed. Any input on the subject? :blink:

Luck is at the intersection of planning and opportunity.

[kid442]

Deuce,
I have converted two 63 Jetfires. I have just acquired back my first car. I will attach a few photos. The car I have now I just screwed the 4-speed hump in place. The second car I spot-welded it. I could tell the difference between the two cars when driving. If you need any help or information please feel free to give me a call.
Good luck and keep in touch.
Ken Dennison
732-870-6964
kid442w30@yahoo.com

[deucephaeton]

Thanks.
That’s the parts I have. Spot weld them in is the plan then.
I’m sure glad I noticed the trans tunnel was different when I bought the 4-speed stuff. Could have been a disaster had I not seen it. Would have been a lot more work to make a piece. 😛

Luck is at the intersection of planning and opportunity.

[62oldsf85]

Don’t know if you’re still doing this, I ended up using a 62 Nova shift hump in mine. I didn’t notice the difference in the tunnels until I tried to put the trans in for a dry fit, and then had to cut and weld. It works just fine.

[macf85]

I made this modification in the same way that kid442 did. I was lucky enough to find an original ’63 Cutlass with the entire 4-speed setup still intact. I got the bellhousing, clutch, flywheel, pedals and clutch release mechanism, transmission and the partial floor pan/transmission tunnel. The factory did cut out the auto. trans. tunnel on the assembly line and welded in a partial stamping to accommodate the trans. shifter. You’ll probably have a hard time finding an original car that was a 4-speed though.

[deucephaeton]

Actually I found a complete 4-speed drive line out of a wrecked 62 F-85. Bought it from the flywheel to the rear end. Pedal assembley and linkage with trans hump too. Bonus! Thanks for the reply.

Luck is at the intersection of planning and opportunity.

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