1-2-b-67L89

Did GM have 10.5 or 11 inch clutch from the factory on 1967 427 Corvettes or were some 10.5 and some 11 inch (L88?)? I thought they were all 11 inch but ?
Thanks to the experts out there.

buns

If memory serves me correctly, I believe I read on this forum that all big blocks had the 11" clutch, except the L88 which used the 10.5". The reason for it was never explained. Why would you use the smaller clutch on the higher output motor?

My theory is that they wanted you to fry the clutch before you pretzeled the halfshafts, or corkscrewed the driveshaft causing it to to rip through the floorboards.


p.s. My theories have been known to be faulty.

63Corvette

427s had an 11" clutch.......except for L88s, which had a 10.5" clutch....along with a unique (smaller) flywheel and different starter location.

67pete

10.5" for racing the L88..

Steve439

The L88 clutches were special heavy-duty units.

The smaller, lighter flywheel revs faster in road racing applications.

AZDoug

And on the drag strip. It just doesn't have as much hole shot inertia.

Doug

Ironcross

Another way of description is that 99.9 % were 11 inch.

To most analyzers the 11 in. would seem be the heavy duty application not a smaller one. However with the tighter winding L88, it`s the 10 3/8 lightweight unit that is the real HD racing clutch assembly that was acknowledged by nearly all the above replies.