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#1
10-25-2017, 07:31 PM
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Clutch size
I recently purchased a bellhousing, flywheel, clutch and pressure plate off Craigslist, supposedly from a late 60's GTO. I had the guy measure the clutch diameter for me before hand, the size seems odd to me, hopefully someone can help. Outside diameter is almost 12 inches, I've attached a picture. I can't find much info online to help me with it, guy didn't have part numbers. Any help appreciated.
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#2
10-26-2017, 06:02 AM
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If I am not mistaken 11" clutch set ups never came factory standard in SM GTO's until the 455 came to be in 1970, but I don't know maybe it was a option?
__________________
Wernher Von Braun warned before his retirement from NASA back in 1972, that the next world war would be against the ETs! And he was not talking about 1/8 or 1/4 mile ETs! 1) 1940s 100% silver 4 cup tea server set. Two dry rotted 14 x 10 Micky Thompson slicks. 1) un-mailed in gift coupon from a 1972 box of corn flakes. Two pairs of brown leather flip flops, never seen more then 2 mph. Education is what your left with once you forget things! |
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#3
10-26-2017, 06:56 AM
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Is it considered 11"? It measures almost 12" outside to outside.
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#4
10-26-2017, 07:07 AM
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I don't think it's factory then!
__________________
Wernher Von Braun warned before his retirement from NASA back in 1972, that the next world war would be against the ETs! And he was not talking about 1/8 or 1/4 mile ETs! 1) 1940s 100% silver 4 cup tea server set. Two dry rotted 14 x 10 Micky Thompson slicks. 1) un-mailed in gift coupon from a 1972 box of corn flakes. Two pairs of brown leather flip flops, never seen more then 2 mph. Education is what your left with once you forget things! |
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#5
10-26-2017, 07:09 AM
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Quote:
Take a piece of cardboard and measure 11" flat across the surface and make two magic market lines. Then lay the clutch disc so that it is centered on the cardboard and look straight down at one side of the clutch disc and position it on the mark. Go to the other side and look down and the clutch disc should be close to the line measuring 11" Tom V.
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"Engineers do stuff for reasons" Tom Vaught Despite small distractions, there are those who will go Forward, Learning, Sharing Knowledge, Doing what they can to help others move forward. |
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#6
10-26-2017, 02:04 PM
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Does the clutch disc fit the pressure plate?
Does the pressure plate fit the flywheel? Is the flywheel for a Pontiac? May have come out of a late 60s GTO...But who knows what engine it had in it... Clay
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All the federales say,they could've had him any day They only let him slip away, out of kindness...I suppose Poncho & Lefty |
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#7
10-26-2017, 07:14 PM
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Quote:
1) A-Body and F-Bird) will come stock with a 10.5" Clutch Disc and matching pressure plate. (Not a LMY (Later Model Year) GTO expert. some 455 engines may have had a 11" pressure Plate and clutch disc like the Chevelles had. 2) You can use a 10.5" disc on a 11" pressure plate on a flywheel drilled for a 11" Pressure Plate. Most Aftermarket Flywheels are drilled for both patterns. 3) You cannot run a 11" disc on a 10.5" pressure plate. Will not fit. Hope that helps. Tom V. ps Some of the friction materials out there for Clutch discs are designed for higher temps/higher static pressure plate loads and work ok for street strip. The Dual Friction stuff comes to mind.
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"Engineers do stuff for reasons" Tom Vaught Despite small distractions, there are those who will go Forward, Learning, Sharing Knowledge, Doing what they can to help others move forward. |
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#8
10-26-2017, 10:59 PM
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I believe McLeod and some others offer(ed) a 12" "cheater" clutch which was described as a truck 12" disc with special pressure plate to fit a flywheel drilled for a regular 11" clutch.
Maybe that's what you have?
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Michael  1970 Oshawa built 1 option Judge. 24 year restoration/upgrade project finally finished! 1979 Trans Am - low-buck drag car project for when I retire |
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#9
10-27-2017, 11:14 AM
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True, McLeod does make clutches that don't adhere to the standard size/measuring, but technically, when measuring, you measure the bolt pattern of the plate to get the dimension of the 'clutch assembly'. But those also I believe never work out to a 'true' 10.5 or 11 setup.
Some reason the 10.5 disc measurement is something like 10.95, but that's straight from memory. I used to have the measurement for the bolt patterns, but I would have to dig thru piles of notes. (pre-computer days) There's no markings on the disc or plate? Take a pic of the plate and post too. .
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. 1970 GTO Judge Tribute Pro-Tour Project 535 IA2 http://forums.maxperformanceinc.com/...d.php?t=760624 1971 Trans Am 463, 315cfm E-head Sniper XFlow EFI, TKO600 extreme, 9", GW suspension, Baer brakes, pro tour car https://forums.maxperformanceinc.com...ght=procharger Theme Song: http://www.youtube.com/watch?v=7zKAS...ature=youtu.be |
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#10
10-27-2017, 11:45 AM
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Quote:
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72 lemans,455 e-head, UD 255/263 solid flat,3.73 gears,,,10" 4400 converter,, 6.68 at 101.8 mph,,1.44 60 ft.2007 (cam 271/278 roller)9"CC.4.11gear 6.41 at 106.32 mph 1.42 60 ft.(2009) SOLD,SOLD 1970 GTO 455 4 speed #matching,, 3.31 posi.Stock manifolds. # 64 heads.A factory mint tuquoise ,69' judge stripe car. 8.64 @ 87.3 mph on slippery street tires.Bad 2.25 60ft.Owned since 86' |
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#11
10-27-2017, 03:40 PM
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Definitely an aftermarket 12" clutch (possibly truck). Not sure they will fit in the stock aluminum BOP bellhousing though. Did you get an aftermarket bellhousing? The larger 12" disc is a little bit more difficult to shift quickly at high rpm due to the synchros trying to manage the higher inertia. The pressure plate will bolt to the flywheel just fine.
Sent from my SM-T817V using Tapatalk Last edited by 70GS455; 10-27-2017 at 03:47 PM. |
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