11" bellhousing with 10.5 clutch

[70challengerrt]

I currently have a 11" cast bellhousing with a 11" clutch set up. Because I have a externally balanced motor I had to drill out spots to make the fly wheel to offset the crank. I was considering going back to a 10.5 clutch to help smooth out the motor (it has a slight vibration in the upper rpms). I have a local guy who is consdiering trading my bellhousing for a aluminum 10.5 one because mine is date coded/ casted for a 69 6pak car. If this falls through can I run the 10.5 set up in my bellhousing as long as I use the 11" clutch fork?

[KellysCuda aircard]

no , the flywheel will not be drilled for the 10.5/10.95 pattern & to use the cast bel you need the 143 tooth flywheel 

[ShelbyDogg]

Why do you think that putting on a smaller clutch will fix your high speed vibration? Did you have your flywheel drilled to the specs fot the correct offset balance? If you did, then the only way to correct the balance problem is to send the whole rotating assembly out to the balancer and have it spin balanced. Do you have the correct balancer on the front?

[70challengerrt]

Yes I drilled it for the offset balance but even being off just a fraction can throw it off a little. I had a very good machinest do it. I mean the vibration is very slight (after 5300 rpm) but it wasn't there a few years ago before I switched to the bigger set up. Back then I was going to build the motor up so I figured I would need the bigger clutch, now with gas prices I will let my stock set up in and run the cheap gas and get decent milage.

[ShelbyDogg]

Are you sure that it the engine vibrating?  Can you push in the clutch at high speed, drop the rpms, and NOT feel the vibration when rolling at say 95 MPH?

Rob

[70challengerrt]

I can simulate the vibration in every gear and in nuetral when I come close to that rpm (which is rare). I push in the clutch and it is still there. Like I said if I can get that guy to trade I would rather the 10.5 clutch with the aluminum bell for weight, and running headers reasons anyway but then I can use my old set up which doesn't have that many miles. I should post it in trade section on here if he doesn't what to swap, maybe someone else wants the bigger setup.

[ShelbyDogg]

Just remember that if you go to the smaller bell, you also have to change your flywheel, then have it drilled too. That bigger flywheel is now also modified and would have to be balanced for whatever it ends up on. Be sure to say that when you sell it or the balance woes will continue to the next guy.
I assume that you are running a 440 cast crank? Do you have the correct balancer on the front?

Rob

[70challengerrt]

Yes its a cast crank. The front balancer is correct. I have the smaller flywheel and clutch already, it had about 3000mi before I got the bright idea to go to the bigger set up. I ment I would just post the bell not the flywheel. I would keep the flywheel to turn in as a core.

[Chryco Psycho]

Brewwers sell a new alum bel for the 10.5/10.95" 130 tooth flywheel