Clutch Sizing Questions - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Gibbelstein · 08-18-2006, 06:09 PM

So it's time to replace the clutch on the '69. I have seen an array of sizes, etc. So, I have a few questions:

First off: Which do I need for a '69 c10, 1/2 ton, 2 wheel drive, 250 I6, 3 on the tree, power nothing.

Secondly: For future user's search purposes, if anyone knows a formula or resource that searchers can use in the future, would you mind sharing it? Maybe this can take the place of the multiple "what size do I need" threads I found when I searched.

Third: I went by the parts store and they said they listed 10", and 11" and they couldn't get one of them at all. Do they use the same pressure plate? If I had one and they only sold the other, could I use the one they could get? I.E. if I have 10, could I use the 11 without a problem (or vice versa)?

Thanks in advance for any help I can get.

Chris

**truckdude239** · 08-18-2006, 08:07 PM

should be an an 11 inch clucth

**kwmech** · 08-18-2006, 09:30 PM

Get the 11'' in the diaphram style, same clamping pressure and easier on the linkage, and smoother operation

crazy longhorn · 08-19-2006, 10:15 AM

For the 1/2 ton I- 6, you should have the 10" clutch. The 11" clutch wont fit the bolt pattern on that flywheel.....however, if you go to the smallblock flywheel, you can fit an 11 or 12" on it. Best of luck...

L

shelby987 · 08-20-2006, 09:47 PM

I have a "heavy duty" clutch option on my K20 with a 250ci and a 3spd. I was told this meant I had a 12" clutch?

Can you elaborate on the "smoother operation" ?? Also, do heavy duty clutches come with stiffer pressure plates, or is it purely a clutch disc area kinda thing?

Green Machine · 08-21-2006, 12:35 AM

The 250 inline 6 we removed from our 1970 C10 3 speed had an 11 inch clutch, same as most small block trucks. Get the pressure plate with the raised fingers and the short release bearing, better setup IMHO.

crazy longhorn · 08-21-2006, 09:29 AM

I had a 71 C/10, 6 -250 with 3 spd & it was equipped with the 10" clutch. This was a "bare bones" truck, so it may be how it was ordered or optioned, that makes the difference? The flywheel was the same 14" diameter pc that the 11 & 12" plates fit on......but it was drilled differently. Tear it down ,to see what you have before ordering parts

best of luck,

L

Gibbelstein · 08-21-2006, 08:02 PM

Wow, thanks guys. I put it on a lift the other day and pulled the cover, and I *believe* it is an 11.

It seems odd that there is not some kind of pattern. At least not that anyone has found. Hmm, I guess I'll keep looking around.

Thanks again,
Chris

08-18-2006, 06:09 PM	#1
Gibbelstein Registered User Join Date: Aug 2005 Location: Omaha Posts: 15	Clutch Sizing Questions So it's time to replace the clutch on the '69. I have seen an array of sizes, etc. So, I have a few questions: First off: Which do I need for a '69 c10, 1/2 ton, 2 wheel drive, 250 I6, 3 on the tree, power nothing. Secondly: For future user's search purposes, if anyone knows a formula or resource that searchers can use in the future, would you mind sharing it? Maybe this can take the place of the multiple "what size do I need" threads I found when I searched. Third: I went by the parts store and they said they listed 10", and 11" and they couldn't get one of them at all. Do they use the same pressure plate? If I had one and they only sold the other, could I use the one they could get? I.E. if I have 10, could I use the 11 without a problem (or vice versa)? Thanks in advance for any help I can get. Chris

08-18-2006, 08:07 PM	#2
truckdude239 Senior Member Join Date: Sep 2005 Location: Lewisville, Nc Posts: 10,236	Re: Clutch Sizing Questions should be an an 11 inch clucth __________________ David fuller Ase Certified Mechanic Click here to help support our board!! 1971 Chevy c-10 under going a 4.8l LSx swap Build Thread http://67-72chevytrucks.com/vboard/s...d.php?t=421305 2007 Honda Accord my daily 145kmiles 2002 Honda Accord 4 door With 330k(sisters car) 2005 toyota Avalon 228k( brothers car) 2002 Sububran 5.3 245k 2000 Tahoe 5.3l 378 General manager for Marco's Carwash & lube

08-18-2006, 09:30 PM	#3
kwmech Senior Member Join Date: Mar 2003 Location: Colfax-California Posts: 8,574	Re: Clutch Sizing Questions Get the 11'' in the diaphram style, same clamping pressure and easier on the linkage, and smoother operation

08-19-2006, 10:15 AM	#4
crazy longhorn Fabricate till you "puke" Join Date: Jun 2002 Location: Ill Posts: 9,403	Re: Clutch Sizing Questions For the 1/2 ton I- 6, you should have the 10" clutch. The 11" clutch wont fit the bolt pattern on that flywheel.....however, if you go to the smallblock flywheel, you can fit an 11 or 12" on it. Best of luck... L __________________ 69 longhorn,4" chop,3/5 drop, 1/2 ton suspension/disc brakes,1 1/2" body drop,steel tilt clip, 5.3/Edelbrock rpm intake/600 carb, Hooker streetrod shorties,2 1/2" exhaust/ H pipe/50's Flows , 6 spd Richmond trans,12 bolt/ 3.40 gears....

08-20-2006, 09:47 PM	#5
shelby987 Registered User Join Date: Mar 2005 Location: Just outside Durham, NC Posts: 894	Re: Clutch Sizing Questions I have a "heavy duty" clutch option on my K20 with a 250ci and a 3spd. I was told this meant I had a 12" clutch? Can you elaborate on the "smoother operation" ?? Also, do heavy duty clutches come with stiffer pressure plates, or is it purely a clutch disc area kinda thing? __________________ 1969 SS 350 Camaro Sold 2008 1970 3/4T K20, stock height with 33's, 250 I6, 3 on the tree, and locked front and rear 4.10's 1980 Chevy Malibu 2 dr Sold 2007 1993 Olds. Cutlass Ciera Wagon Traded 2006 2003 Saturn L200 w/5pd. D/D My list spans 5 decades with One common thread.....GM!

08-21-2006, 12:35 AM	#6
Green Machine Senior Member Join Date: Jul 2004 Location: Estherville, Iowa Posts: 3,371	Re: Clutch Sizing Questions The 250 inline 6 we removed from our 1970 C10 3 speed had an 11 inch clutch, same as most small block trucks. Get the pressure plate with the raised fingers and the short release bearing, better setup IMHO. __________________ 1968 C10 307 3spd Long Fleet ------ http://67-72chevytrucks.com/vboard/s...d.php?t=201103 1970 C10 305 Super T10 Long Fleet --- http://67-72chevytrucks.com/vboard/s...d.php?t=202285 1971 C20 383 TH350 Dana Posi ----- http://67-72chevytrucks.com/vboard/s...d.php?t=206894 2001 GMC Sierra 1500 C3 6.0

08-21-2006, 09:29 AM	#7
crazy longhorn Fabricate till you "puke" Join Date: Jun 2002 Location: Ill Posts: 9,403	Re: Clutch Sizing Questions I had a 71 C/10, 6 -250 with 3 spd & it was equipped with the 10" clutch. This was a "bare bones" truck, so it may be how it was ordered or optioned, that makes the difference? The flywheel was the same 14" diameter pc that the 11 & 12" plates fit on......but it was drilled differently. Tear it down ,to see what you have before ordering parts best of luck, L __________________ 69 longhorn,4" chop,3/5 drop, 1/2 ton suspension/disc brakes,1 1/2" body drop,steel tilt clip, 5.3/Edelbrock rpm intake/600 carb, Hooker streetrod shorties,2 1/2" exhaust/ H pipe/50's Flows , 6 spd Richmond trans,12 bolt/ 3.40 gears.... Last edited by crazy longhorn; 08-21-2006 at 09:31 AM. Reason: spelling

08-21-2006, 08:02 PM	#8
Gibbelstein Registered User Join Date: Aug 2005 Location: Omaha Posts: 15	Re: Clutch Sizing Questions Wow, thanks guys. I put it on a lift the other day and pulled the cover, and I believe it is an 11. It seems odd that there is not some kind of pattern. At least not that anyone has found. Hmm, I guess I'll keep looking around. Thanks again, Chris



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