4 speed big block question - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**68350** · 06-17-2006, 11:10 PM

Is the factory big block 4 speed clutch linkage different from a small block 4 speed? thanks

**Tom Vogel** · 06-18-2006, 12:08 AM

I would assume it is different. the Z-bar should benarrower on the BBdue to the extra width of the motor. You could narrow thw z-bar though. Ive got a BB setup and could email you a picture, however its out of the truck as Im trying to fit a set of headers. If out of the truck is ok, Ill send some pictures.

**68350** · 06-18-2006, 06:54 PM

I was just wondering before I gave away my big block set up I have on my longhorn. I thought they were different, but wanted to make sure. thanks

**Tom Vogel** · 06-18-2006, 09:13 PM

Give it away? I paid $275 10years agofor mine.. It was NOS but... give it away$?

71/454 · 06-19-2006, 04:49 AM

Has anyone ever measured one? I ask because I'm doing this conversion. I look at where the z bar pivot ball bolts to on the block and it is right near the bellhousing on both big and small, same position in reference to the width of the bellhousing. And since all bellhousings are the same on a chev this makes me think that the z bar width is the same. The only thing that makes me think something may be different is that I6 small block and bbc used differrent mounts, some engines sat more forward and more back than others, so this may affect some of the rod lengths. But like I said i don't know for sure, anybody else have any idea's?

**special-K** · 06-19-2006, 12:07 PM

Some pivot balls mount directly to the block,some mount to brackets that bolt between the ball pivot mounting hole and a rearward threaded hole.The location of the pivot ball on the bracket varies for different engine locations in the frame,2wd/4wd.I`m not sure how to tell a BBC linkage from a SBC,though.

sakohntr · 06-22-2006, 12:45 PM

The linkage is the same. When i converted from sbc to bbc, i used all the same pieces. And when i slid everything forward to accomodate an HEI i also had to move the frame bracket forward as well. The only mod i made was in shortening the clutch fork push rod to accomodate the new distance in length. Works perfect.

Blazerb61 · 06-22-2006, 01:30 PM

I use a hydralic throwout bearing that works well also

06-17-2006, 11:10 PM	#1
68350 Senior Member Join Date: Jan 2002 Location: Williston, ND Posts: 2,999	4 speed big block question Is the factory big block 4 speed clutch linkage different from a small block 4 speed? thanks __________________ 68 Chevy CST/10, 50th Anniversary, 327/th400, 373 posi, buckets 68 GMC Shortbox Stepside, 402/th400, Tilt, Tach, Bucket Seats, 3.08 Positraction 69 Chevy Camaro SS, 383, 4 speed, positraction 70 Chevy El Camino SS396, Triple Black, 454/th400, Tach 70 Chevy Shortbox Stepside 4x4, 350/th350, Tilt, Tach, Cab Lights, Bumper Guards, Tow Hooks 70 Chevy 3/4 Longbox, 350/auto, 70k, SURVIVOR 71 Chevy Blazer, CST, 350/auto 71 GMC Sierra K2500, 454, 4 speed, 4.10 posi, 37s 71 Custom/30, Open Road, 350/th400, tilt 72 Chevy Shortbox Fleetside, 496 Stroker/th400, Tilt, Tach, Bucket Seats, 3.42 Posi 72 GMC Sierra Grande 2500. 427/th400, tilt, a/c, tool and stowage, buckets/console, 3.54 posi

06-18-2006, 12:08 AM	#2
Tom Vogel 2WD Jimmy Join Date: Mar 2005 Location: Davis County, Utah Posts: 2,565	Re: 4 speed big block question I would assume it is different. the Z-bar should benarrower on the BBdue to the extra width of the motor. You could narrow thw z-bar though. Ive got a BB setup and could email you a picture, however its out of the truck as Im trying to fit a set of headers. If out of the truck is ok, Ill send some pictures.

06-18-2006, 06:54 PM	#3
68350 Senior Member Join Date: Jan 2002 Location: Williston, ND Posts: 2,999	Re: 4 speed big block question I was just wondering before I gave away my big block set up I have on my longhorn. I thought they were different, but wanted to make sure. thanks __________________ 68 Chevy CST/10, 50th Anniversary, 327/th400, 373 posi, buckets 68 GMC Shortbox Stepside, 402/th400, Tilt, Tach, Bucket Seats, 3.08 Positraction 69 Chevy Camaro SS, 383, 4 speed, positraction 70 Chevy El Camino SS396, Triple Black, 454/th400, Tach 70 Chevy Shortbox Stepside 4x4, 350/th350, Tilt, Tach, Cab Lights, Bumper Guards, Tow Hooks 70 Chevy 3/4 Longbox, 350/auto, 70k, SURVIVOR 71 Chevy Blazer, CST, 350/auto 71 GMC Sierra K2500, 454, 4 speed, 4.10 posi, 37s 71 Custom/30, Open Road, 350/th400, tilt 72 Chevy Shortbox Fleetside, 496 Stroker/th400, Tilt, Tach, Bucket Seats, 3.42 Posi 72 GMC Sierra Grande 2500. 427/th400, tilt, a/c, tool and stowage, buckets/console, 3.54 posi

06-18-2006, 09:13 PM	#4
Tom Vogel 2WD Jimmy Join Date: Mar 2005 Location: Davis County, Utah Posts: 2,565	Re: 4 speed big block question Give it away? I paid $275 10years agofor mine.. It was NOS but... give it away$?

06-19-2006, 04:49 AM	#5
71/454 Turbo Guy Join Date: Jan 2005 Location: Calgary Alberta Posts: 353	Re: 4 speed big block question Has anyone ever measured one? I ask because I'm doing this conversion. I look at where the z bar pivot ball bolts to on the block and it is right near the bellhousing on both big and small, same position in reference to the width of the bellhousing. And since all bellhousings are the same on a chev this makes me think that the z bar width is the same. The only thing that makes me think something may be different is that I6 small block and bbc used differrent mounts, some engines sat more forward and more back than others, so this may affect some of the rod lengths. But like I said i don't know for sure, anybody else have any idea's?

06-19-2006, 12:07 PM	#6
special-K Special Order Join Date: Nov 2004 Location: Mt Airy, MD Posts: 85,851	Re: 4 speed big block question Some pivot balls mount directly to the block,some mount to brackets that bolt between the ball pivot mounting hole and a rearward threaded hole.The location of the pivot ball on the bracket varies for different engine locations in the frame,2wd/4wd.I`m not sure how to tell a BBC linkage from a SBC,though. __________________ "BUILDING A BETTER WAY TO SERVE THE USA"......67/72......"The New Breed" GMC '67 C1500 Wideside Super Custom SWB: 327/M22/3.42 posi.........."The '67" (project) GMC '72 K2500 Wideside Sierra Custom Camper: 350/TH350/4.10 Power-Lok..."The '72" (rolling) Tim "Don't call me a redneck. I'm a rough cut country gentleman" R.I.P. ~ East Side Low Life ~ El Jay ~ 72BLUZ ~ Fasteddie69 ~ Ron586 ~ 67ChevyRedneck ~ Grumpy Old Man ~

06-22-2006, 12:45 PM	#7
sakohntr Registered User Join Date: Mar 2002 Location: Floodwood Minnesota Posts: 1,057	Re: 4 speed big block question The linkage is the same. When i converted from sbc to bbc, i used all the same pieces. And when i slid everything forward to accomodate an HEI i also had to move the frame bracket forward as well. The only mod i made was in shortening the clutch fork push rod to accomodate the new distance in length. Works perfect. __________________ 1967 K30 Napco 292/SM420 original paint 30k miles 1968 K60 Napco 396/5spd. dbl frame 52" michelins 1969 K10 SWB GMC 454/4spd 6" 35's posi,hooks 1972 C30 longhorn,BB/AT,A/C,Tilt,Toolbox,lokr 1987 K20 Chevrolet Suburban. 6" lift. 5.7L/TH400 1979 K60 GMC Coleman 4x4, 427/Allison.

06-22-2006, 01:30 PM	#8
Blazerb61 Registered User Join Date: Aug 2005 Location: Davenport Iowa Posts: 115	Re: 4 speed big block question I use a hydralic throwout bearing that works well also



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