Joe, to the best of my knowledge no cars came with 12" clutches - trucks only. The problem with a truck bellhousing is the hole for the bearing retainer is bigger (this is what aligns the engine to the trans). You will probably have to go to an 11" clutch to fit in a car bellhousing. Good luck, Jim.
I have bought a couple of cars which had 12" flywheels installed at some point. Both had a bellhousing that was basically two pieces. The bottom portion was basically 1/3rd of the bellhousing it was very unsightly at best. I would stick with a 11" if it were my car.
Well that is a disheartening bit of info. I thought the tranny aligned to the motor by sliding the input shaft in.... Is there just no way it can work?
I got a truck bellhousing, hopefully it works out. I'll try to install it tonight if possible
My car had a truck clutch/flywheel set-up when I got. When I went to replace it, the shop i was dealing with at the time suggested that turning the bigger clutch was an unecessary waste of HPs (so I switched).... just a thought, good luck on the install and let us know how it went.
Ron Cook TC Gold Member #1276
1969 300 Deluxe HTSS39669 300 Deluxe325HP L3569memorylane 1971 Malibu 2DR HT "Supporting all car hobbyists, even those with different cars, is what being a true enthusiast is all about."
There is a tradeoff with the clutch size. If you go to big it will cost you horsepower, and more importantly a large clutch has more mass, therefore more centrifical force and more potential for explosion. Yeow! The really trick setup is tandem 10" clutches (more area, less mass, half the pedal pressure due to half the pressure plate force required by the smaller clutch disks sharing the load.) Unfortunately it was a really obscure option on the '69 models (again on the '71 Olds W30). Pity. As for conventional clutches, just remember about diminishing returns. I'd say an 11" would be plenty.
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