[birdturd]

I am considering swaping my 400 for a 455 in my '67 'bird. Should I be using a 11" disk for the 455 or is 10 1/2 adequate? Is the flywheel different between 11 and 10 1/2" clutches.

[birdturd]

I am considering swaping my 400 for a 455 in my '67 'bird. Should I be using a 11" disk for the 455 or is 10 1/2 adequate? Is the flywheel different between 11 and 10 1/2" clutches.

[PMD428]

When I was talking to centerforce the other day about the same thing. I was told when you are near 500 hp they want to see the 11". I told him my flywheel was drilled for the 10.5" he found me an extra heavy duty Dual friction for the 10.5" that I did not see on there web site.

Stand out in the crowd, drive a Pontiac.

[birdturd]

cool. thanks.
Anybody else have any comments or info on this ?

[63Banshee]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by birdturd:
I am considering swaping my 400 for a 455 in my '67 'bird. Should I be using a 11" disk for the 455 or is 10 1/2 adequate? Is the flywheel different between 11 and 10 1/2" clutches.<HR></BLOCKQUOTE>

Talk to the guys at McLeod. You will not need to place another phone call.

L8r,
DJ

63 Cat vert: 389, tri-power (aftermarket), 4-spd, 3.42:1, 8-lugs, a/c, pb, ps, silverleaf green, tri-fawn interior, white top.

1964 GTO HT: Bare bones 389, tri-power, 4-spd, 3.90:1, Cameo Ivory (original color), black interior.

1968 Vette Roadster: 327/300, 4-spd, 3.90:1, Lemans blue, blue interior, convertible delete.

[BAD ANDY]

I've had the pleasure of changing a few clutches & I'd say take the time and try to find an 11" set up. Think of it like a tool box. We always say it'll be big enough then it's not.

[455-4+1]

Talk to McLeod about one of their soft lok assemblies. Low pedal effort, sintered iron disk, adjustable pressure plate (static and centrifugal)

If you up your power at a later date you can adjust your pressure plate to suit. Pedal pressure is very low (ususally between 700-1500lb plate load) and very drivable. They offer a sprung hub version for more street-strip use and you can upgrade to a solid hub for racing later if you wish

Disks come in different compounds (5191, 5135 etc)

Go with the complete package and you wont look back

A common setup is running a 10.5" disk on an 11" pressure plate. This allows the pressure ring to act as a heat soak and allows you to upgrade to an 11" disk later if needed (you wont need to)

Talk to McLeod

Working on going faster!!!

[unclescratch]

I don't doubt that the intended use has a lot to do with this, but it seems to me that all 455's leaving the Pontiac assembly lines had 11" clutches between them and their manual transmissions. Why do you suppose they did that ??? Torque ??

[larry davis]

Big cubes, high torque = 11"
I wouldn't use less even on a stock 400.

Not sure, but I don't believe Pontiac used any 10.5s on any performance applications?



SECOND AMENDMENT: AMERICA'S ORIGINAL HOMELAND SECURITY.
Bob is Scott!

[larry davis]

Forgot: higher wieghts = 11".



SECOND AMENDMENT: AMERICA'S ORIGINAL HOMELAND SECURITY.
Bob is Scott!

[ontheblocks]

The most important reason, is the 11 inch has more contact area for the clutch to grab, hence, it can handle more torque!

If it has ti*s or tires, it's gonna cost ya!

[birdturd]

So then the flywheels are different between 10 1/2 & 11 (bolt circle diameter) ? Any specs on this so that I can verify ?

[birdturd]

I will not be racing this setup. This will be a cruiser that I'll want to occasionally smoke the tires (245's - 265's) just don't want to smoke the clutch.

[sdbob]

I'm glad someone asked the question 10.5/11. Because 10 yrs ago I had an 11" flywheel so I bought a 11" centerforce clutch setup but never used it in my 67.At least now I feel I did the right thing. Now can I use the stock 11" flywheel on a 400 without balancing?

[63Banshee]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by birdturd:
I will not be racing this setup. This will be a cruiser that I'll want to occasionally smoke the tires (245's - 265's) just don't want to smoke the clutch.<HR></BLOCKQUOTE>

Have you called McLeod yet? Tell them your setup, how you drive, and they will pick out the best system for your application. Trust me.

[birdturd]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by 63Banshee:
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by birdturd:
I will not be racing this setup. This will be a cruiser that I'll want to occasionally smoke the tires (245's - 265's) just don't want to smoke the clutch.<HR></BLOCKQUOTE>

Have you called McLeod yet? Tell them your setup, how you drive, and they will pick out the best system for your application. Trust me.<HR></BLOCKQUOTE>

Haven't called yet. Need money for the 455 ! It is close !!

[455-4+1]

11" Vs 10.5" disk using the same pressure plate load (2800 in this case), same static friction coefficeint (0.34 (SAE J-866a "E")in this case) calcs out to a 25 lb/ft difference in torque capacity with the 10.5" disk showing a slightly higher linning pressure of 67 psi Vs 64 for the 11". (mean effective radius based on friction ID at 20% of OD). Bear in mind the larger disk will have more inertia for a shifting application.

It is my understanding that the increased capacity of the larger disk comes from the larger mean effective radius of the disk rather than the increased surface area (increases surface area will lessen the clamping force seen by the disk resulting in a lower linning pressure using the same pressure plate load)

With most "street" organic type linnings, (similar friction compounds) pressure plate load has the greatest effect on the capacity of a single disk clutch.

Unless a very high coefficent of friction disk is used (aggressive sintered iron or similar) with a correspondingly low pressure plate load I would be a little hesitant to rely too much on centrifugal assist in a street driven 455 limited to moderate RPM

Just my opinion

(Call Mcleod)

Working on going faster!!!