Here are photos of my original flywheel after about 10,000 miles on a clutch. The original flywheel surface is only 10.75" diameter. The 11" clutch will hang past the friction surface. I didn't figure this was a problem...

...except that it wears an edge on the clutch disc, which then digs into the flywheel bolt areas. This tore a chunk off the clutch disc.





The disc is also cracked elsewhere, not sure if that's related, or just a cheap clutch. Either way I replaced it. It never held that well anyways, maybe the uneven clamping force had something to do with that.

This time around I used a flywheel from Kragen, Standard Flywheels #6516, it's heavier than the stock piece, but the friction surface is larger. It was a little thinner than the stock piece too, but this didn't cause any issues with my ZF clutch setup.










So YES an 11" ZF clutch can be used on the 84-85 if you change the flywheel. The pressure plate bolt pattern from 84-96 is exactly the same.

Interesting...

I see you still refuse to use a sprung hub...

Sprung hub is NOT an option, check the flywheels in the 3rd photo, it doesn't fit. Maybe there are 2-pc rear main flywheels out there with a really deep dish to clear the sprung hub, but I don't know which, and they may end up being too thick for the clutch set to fit in this very small ZF bellhousing.

I should let you drive it next time I'm up, you'll see it's not an issue.

I drove it last time, and it wasn't that bad, really...

I forgot, you have a 2 piece seal... ok... forget that then.

I thought it was grabby due to that, but it was actually from the clutch engaging too high. Seems to be fixed with the ZR1 pressure plate. The throttle body gets sticky off idle when hot too, which is aggravating.

I'm putting in new hydraulics tomorrow though, so we'll see what that does. Seems like people slap these things together and if it functions, it's good as gold to them. I'm a picky SOB.

well, yea, we know that...

IF that is the same flywheel we put on mine.....I couldn't be happier.

I have to track down a U-joint or something on the driveline that worn out and causing a bit if what could be clutch chatter....but on a brand new clutch, there is no way it is chattering. Plus when I reverse quickly, I can feel something towards the rear end......how can I say it......almost slipping for just a moment and then grabbing. Like a u-joint turning in worn journals.

You sure it's not your rear spindles slipping? You just had someone replace the rear bearings right? These will shift on initial movement, then they shutup.

I think the rear spindles are twisted or slightly loose or the u-joint has let go.

Honestly, I've been lazy about getting it checked. But it is one of the sources of my high speed vibration I told you about months ago.

1). Rear end drive train vibration, Right side
2). Left Front suspension bushing is out.

But the Clutch is great.

I've been picking off these little annoyances one at a time.