[Joel Koontz]

Changing clutch on 68 Firebird.

Currently has 10.5" clutch. Will an 11" clutch work with the existing flywheel?(the FW will be turned)

Fairly low performance 400. Street use only. Would 10.5" or 11" be better?

[Firebob]

The 10.5 is fine but if you change to an 11" you have to get a FW that is drilled for both. The stock Firebird one isn't.

[Tom Vaught]

Originally Posted by Firebob

The 10.5 is fine but if you change to an 11" you have to get a FW that is drilled for both. The stock Firebird one isn't.

x2

10.5" flywheel will not accept a 11" cultch but for a street car the 10.5" clutch fits in the bellhousing fine and has all the clutch surface area you need to burn the rubber off your tires.

A 11" clutch was sometimes required when you added slicks to a car with the same friction material as the street tire testing and then the clutch started to slip.

So you went up to the 11" diameter clutch (More surface area) but the spring pressure and the friction material basically remained close to what you had before so no slipping clutches, no jerking clutches, etc. Just now the durability was back due to the additional surface area.

Tom V.

[Joel Koontz]

Thanks! That is what I assumed, but assuming can sometimes get you in trouble.

The flywheel does only have one set of bolt holes so will be using a 10.5" clutch.

I have not bought a clutch in 40 years.

RockAuto lists several brands, Brute Power, M-Pact, AMS Automotive, LUK, SACHS, EXEDY, VALEO.

Any brands to recommend or avoid?

[Tom Vaught]

I have bought LUK clutches in the past.
I run a 11" steel flywheel and it can use the 11" Corvette modern parts and materials.
I also run a scattershield. Pure street car without the beating on the car, the 10.5 clutch parts from LUK should be fine.

Tom V.