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168 tooth Flywheel 10.4" or 11" ?

20K views 8 replies 5 participants last post by  Bryan59EC 
#1 ·
I have a stock flywheel and I'm wondering if it matters what clutch I put on. It's a 14in. flywheel out of a '68 small block, Camaro. The wear pattern was a 10.4", but is there any reason someone couldn't put an 11" on this flywheel?
Thanks for reading.

John
 
#2 ·
10", 10.4", & 11 inch all use the same bolt pattern.

Been a long time, but I think the 12" uses the same pattern.
(had a 12" Borg & Beck in my 79 Chev pu for years)

Pressure plates are different as they generally have the same size plate as the disc.
I have seen people run smaller discs on an 11" pressure plate tho---dunno why.

You will need to get your existing flywheel resurfaced if going to a larger disc---
---good idea if you even stay with the small disc.
 
#4 ·
No, not exactly.
The early 168 teeth flywheels had a bolt pattern for a 10in clutch. The 10in clutch has now been replaced with a 10 1/2in (or if you prefer, 10.4in) clutch which used the SAME bolt pattern for the pressure plate. The FIRST Chevy V8 flywheels were ALLLLLLLLLLLLLL the 168 teeth version up through 1962. Then in 63, the smaller 153 teeth flywheel was introduced. Those flywheels ONLY USED the 10 1/2in clutch.
MOST of the early 168 teeth flywheels had the bolt pattern for a 10 or 10 1/2in clutch. BUUUUUUUUUUUUT, some of the early 168 teeth flywheels (police, taxi, HD, truck, etc) did have a bolt pattern for an 11in clutch.
Soooooooooooooo, here is where I'm going with all of this. Just because a flywheel is the 168 teeth version, IT MUST HAVE THE CORRECT BOLT PATTERN in order to use an 11in clutch!!! Beginning ABOUT 1962-63, MOST 168 teeth flywheels did have the bolt pattern for an 11in clutch.
Now, here is one more variation of the 168 teeth flywheel. SOME of them had a dual bolt pattern which permitted either an 11in or a 10 1/2in pressure plate to be bolted to the flywheel. But those were usually service replacement flywheels.

And, since the 12in clutch was mentioned, it also was used with the 168 teeth flywheel. BOTH 11in and 12in clutches used the same bolt pattern on a 168 teeth flywheel. FROM THE FACTORY, the only 12in clutches used in Chevrolets was truck applications, such as 1ton and larger. The 12in truck clutches required a different bell housing to accomodate the larger diameter of the 12in pressure plate.
There are AFTERMARKET 12in pressure plates that WILL FIT inside the stock pass car bell housing, such as the 621 housing.

Below is a 153 and 168 teeth flywheel. The 168 teeth flywheel has the bolt holes near the edge of the flywheel. This is the bolt pattern necessary for an 11in clutch (or 12in).


Here is one of the early 168 teeth flywheels. Notice the bolt pattern for the pressure plate. This flywheel will ONLY ACCEPT a pressure plate for a 10 1/2in clutch.
 
#6 ·
Clearly, I'm not the sharpest tool in the shed.
I'm getting caught up the wrong stuff, here.
Okay, so end of teeth, to end of teeth my flywheel measures 14".
This tells me it's not a 153 tooth. ???
Next, there are 6 bolt holes evenly spaced like the picture with the early 168tooth; however, the bolt holes are right at the edge. Plus the wear pattern on my flywheel measures 11" in diameter. I mean mistery solved, right? If the wear pattern is 11" than it will accept an 11" clutch.

John
 
#9 ·
Next, there are 6 bolt holes evenly spaced like the picture with the early 168tooth; however, the bolt holes are right at the edge. Plus the wear pattern on my flywheel measures 11" in diameter. I mean mistery solved, right? If the wear pattern is 11" than it will accept an 11" clutch.

John
My bad----the smaller clutches do have a smaller pattern.
If you measure 14" across----you have a 168 tooth flywheel

The flywheel on the right that Tom posted is actually drilled for
a "Long" and "Borg & Beck" / Diaphram clutch plate

The "Long" type clutch is retained by 12 bolts.
It is a "3-finger" type that is commonly found in Ford products

The "Borg & Beck" and the diaphram are retained by 6 bolts
"Borg & Beck" is another type of 3-finger clutch that can utilize rollers
inside the clutch cover to increase holding pressure at hi RPMs
Not sure how well those rollers work, but my old 67 Chrysler 300 used that
type of clutch from the factory.

11" wear pattern + the 6 holes on the edge-----11" clutch
 
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