I came across this on summit's website as I was searching for a new clutch for my 64 ss. I'm just learning about small blocks and the following exerpt from a product description threw me off...

three major clutch types, diaphragm, Borg & Beck, and Long

I have no idea what that means. I have a 327 4sp, what do each of those terms mean (so I know) and which one do I need?

Thanks!

All three are variations on a theme. The diaphragm pressure plate is a single big conical spring with a bunch of slits cut in it to allow the cone to bend. It applies a uniform pressure and is easily compressed. It is used in all GM applications.

A Borg & Beck is used in Fords and Mopars; and is characterized by a series of coil springs under a hat with three fingers that have to be depressed to compress the springs (they look like valve springs). The Borg and Beck like the diaphragm clutch depends upon the spring pressure to hold the disc. Unlike the diaphragm spring which is a single continuous spring, the multiple springs of the Borg and Beck can be removed and replaced with stiffer springs (or mix and match) to customize the bite of the clutch.

Finally the Long style looks like a Borg and Beck except for three counter weights cast onto the three fingers of the pressure plate. Just like the Borg and Beck it can be modified for a stiffer pressure, but in addition to the springs, the counter weights make the clutch hold even tighter as the RPM picks up (of course at high RPM it takes an elephant to push the clutch in to shift so you pick your counter weights with care).

Big Dave

very good info Big Dave! You are a wealth of information for someone determined to learn small blocks. Based on the information presented, I will choose the diaphragm pressure plate for my application.

On a side note, it's crazy to think that "it takes an elephant to push the clutch in at high rpm's" cause in my world of inline fours I don't notice any difference from 1000 rpm's to 8000 rpm's.

I love to learn, and appreciate your help.

very good info Big Dave! You are a wealth of information for someone determined to learn small blocks. Based on the information presented, I will choose the diaphragm pressure plate for my application.

On a side note, it's crazy to think that "it takes an elephant to push the clutch in at high rpm's" cause in my world of inline fours I don't notice any difference from 1000 rpm's to 8000 rpm's.

I love to learn, and appreciate your help.


One word separates the world of big American V-8's and imported inline fours. Torque!

It takes some effort to get it transmitted to the rear wheels and a Long style racing clutch was built to do just that.

Big Dave