which clutch do I have?
 

I have a '67 stepside with a 250-6cyl. The clutch is on it's way out.
Since I live a long ways from any parts store, I want to get a clutch b-4 I tear it down.
My problem is that the parts store shows two clutches for this truck (a 10 and 11 inch). Is there any way to ID my clutch without pulling the tranny? Does anyone know the distance between the adjacent bolts on these clutches, or some other identifying factor?
Thanks

I can't find my resto pack right now but if memory serves, The 3 speeds should have an 10 inch clutch and the 4 speed should have the 11 inch clutch.

Clutch
 

My 71 GMC w/350 4 speed had the 11 inch. Be cautious about the throwout bearing. The one I bought had two listings for bearings, one with cast fork, one for stamped steel fork. Mine had the cast fork. Fortunately I noticed the note on the pressure plate paper work and got the correct one before I left the store. It was suggested to get the flywheel resurfaced which I did. Are you considering that option, or getting a used flywheel and have the surface redone before the job. Get a new pilot bushing for in the crank. I tapped mine and threaded a 5/8"-11 unc bolt thru it and wound it out of the crank. You can also pack it with grease and "press it out". How about a dealer check on one of their old parts books. Hope it gives you some ideas.

TOM,
THAT'S NOT ALWAYS TRUE. I HAD A '67, AND A '71, BOTH WITH SIXES, AND BOTH WITH 11 INCH CLUTCHES, AND BOTH WITH THREE SPEEDS. DADDYBULLFROG, CHECK THE LABEL ON THE INSIDE OF THE GLOVEBOX. SEE IF A HEAVY DUTY CLUTCH IS LISTED. IF SO, CHANCES ARE YOU HAVE AN 11 INCHER. I HOPE THIS HELPS YOU, EVEN IF ONLY A LITTLE. WHILE YOU ARE AT IT , GO TO YOUR LOCAL CHEVY/GMC DEALER, AND GET YOURSELF A NEW PILOT BEARING THAT IS USED FOR THE DIESEL ENGINES WITH A STICK. I REPLACED MY PILOT BUSHING WITH IT, AND IN MY CASE, IT TOOK OUT THE SLIGHT GROAN I HAD IN THE BELLHOUSING AREA. BUT MOST OF ALL IT CUTS DOWN ON THE HEAT AND FRICTION ON THE MAINSHAFT OF THE TRANSMISSION. IT'S CHEAP INSURANCE. :bowtie: :flag: :burnout:

The sticker in the glove box does not list any clutch options. Heavy duty 4 speed, push button raido and custom trim and heater is all that's listed.
Anybody got a 10 or 11 inch laying around that could measure the distance between adjacent bolt holes on the pressure plate? That way I could pull the clutch inspection cover and measure.

Measure This
 

I can measure the one I took out of the GMC but not before the weekend. I'm out of town since I changed mine. Perhaps someone works at an autoparts store and could check for you, or maybe you could call a parts store you usually frequent, ask them to place two on the counter and have them measure for you, then you can check yours in your truck and compare.

MY TRUCK WAS ORIGINALLY A STRAIGHT 6 WITH 3 SPEED. IT HAS A 10".

Your flywheel should be 13 1/2" in diameter, so a 12" disc will measure 3/4" from the edge, a 11" disc will measure 1 1/4" from the edge, and a 10" disc will measure 1 3/4" from the edge.

I just measured a 11" and a 12", don't have a 10" but it should be what I listed.

Jim

The fact that it has a heavy duty 4 speed should also indicate a heavy duty clutch. I can't imagine a 10' clutch with the heavy duty trans option. If still in doubt, you could get both setups on a charge card and return what you don't use and have it credited back to the card. Been there, done that before!

Thanks for all the help. I give all those ideas a try and let you know what I end up with. Most of the parts stores around here have to order it from the "warehouse", so I can't do a stare and compare. I'm trying to get it all done in one day and get the flywheel surface at the same time as I cannot have my truck down for any time. It's my only transportation, and I'm a far piece from the city.

Drop the clutch cover and measure it.That's what I did on mine when I needed to order one.It's been a while but I got enough of a measurement that way to get the clutch ordered.You do need to get the flywheel resurfaced or you may burn the new clutch up from slipping due to glazing of the flywheel.

Thanks for all the help. As best as I can tell it's an 11 in. I'll know 4 sure next week when I tear it down. It's sure nice to get all this help when you need it, and the cost is GREAT!

JimKshortstep4x4, you were right on with those measurements. Mine turned out to be an 11 in like most of us suspected. My clutch fork was pretty worn and I couldn't wait to order one so I had a welding shop build it up and grind it to shape. It now works great. I also had the flywheel resurfaced and replaced the pilot bearing and u-joints. The rear ujoint had no grease fitting and I'm wondering if it could have been original. Anyway, I'm all set up for another 35 years. thanks for all the help from everyone who responded to my question.