Re: 727 Rear Clutch Upgrade worth it?
[Re: Hot 340]
#2415638
12/09/17 09:51 AM
12/09/17 09:51 AM
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Joined: Jan 2003
Posts: 2,933 A shed in England
Tig
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master
Joined: Jan 2003
Posts: 2,933
A shed in England
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We've used the thinner, pre '74 washer in the trans with no issues. Usually lives behind a 655, or a 572 motor when the reserve motor steps in. HTH's
'74 Challenger..9.46 @ 145.9 1/4, 6.001 @ 118 1/8 so far. 4023lb !!! # N/A, Marsh performance 655ci, Indy Maxx, T/R, Indy 600-13 X's, Street legal, pump gas, full interior, Cal-Tracs, mufflers, 3:73's and real 10.5 radials. 9.51 @ 142.4 1/4, 6.003 @ 114 1/8 with our old mule KB, 572-13, 580 wedge. RHD '68 Barracuda Fastback 323ci street/strip. Best ET 13.88 @ 99.03
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Re: 727 Rear Clutch Upgrade worth it?
[Re: Tig]
#2415641
12/09/17 10:21 AM
12/09/17 10:21 AM
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Joined: Dec 2006
Posts: 3,396 Pa
Hot 340
OP
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OP
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Re: 727 Rear Clutch Upgrade worth it?
[Re: Hot 340]
#2415684
12/09/17 12:46 PM
12/09/17 12:46 PM
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Joined: Jan 2003
Posts: 5,991 Anoka County, MN
Leigh
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master
Joined: Jan 2003
Posts: 5,991
Anoka County, MN
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I would upgrade while you have it apart. There are a couple of factors at work. The wave spring allows fore and aft movement, which effectively increases piston travel irrespective of clutch retainer clearance. Not all piston retainer to clutch retainer fit, is the same. The looser the fit, the worse the problem of excessive piston travel and consequential over centering of the spring. If you have a good selection of oem, and aftermarket snap rings, you will find that a combination of 2, will replace the wave spring nicely.
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Re: 727 Rear Clutch Upgrade worth it?
[Re: Hot 340]
#2415766
12/09/17 04:10 PM
12/09/17 04:10 PM
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Joined: Jan 2003
Posts: 25,951 Rio Linda, CA
John_Kunkel
Too Many Posts
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Posts: 25,951
Rio Linda, CA
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The early Belleville works OK when it's new but will fatigue with use and weaken more than the later one. HP has nothing to do with failures, line pressure kills them. Even if they don't break, the early ones can flex enough to allow the piston to pop out of its bore...very common failure.
I've seen a bunch of the early ones fail but never the later one. A worthwhile upgrade IMO.
The INTERNET, the MISinformation superhighway
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Re: 727 Rear Clutch Upgrade worth it?
[Re: Hot 340]
#2416094
12/10/17 09:01 AM
12/10/17 09:01 AM
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Joined: Jan 2003
Posts: 2,933 A shed in England
Tig
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master
Joined: Jan 2003
Posts: 2,933
A shed in England
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Good Info
'74 Challenger..9.46 @ 145.9 1/4, 6.001 @ 118 1/8 so far. 4023lb !!! # N/A, Marsh performance 655ci, Indy Maxx, T/R, Indy 600-13 X's, Street legal, pump gas, full interior, Cal-Tracs, mufflers, 3:73's and real 10.5 radials. 9.51 @ 142.4 1/4, 6.003 @ 114 1/8 with our old mule KB, 572-13, 580 wedge. RHD '68 Barracuda Fastback 323ci street/strip. Best ET 13.88 @ 99.03
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Re: 727 Rear Clutch Upgrade worth it?
[Re: 451Mopar]
#2416447
12/10/17 10:07 PM
12/10/17 10:07 PM
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Joined: Jan 2003
Posts: 25,951 Rio Linda, CA
John_Kunkel
Too Many Posts
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Too Many Posts
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Posts: 25,951
Rio Linda, CA
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The video claims the early piston isn't any different than the late; I've found, by actual measuring, the late piston is taller. The casting number 2124834 ('62-'73) is .783" thick and the 3743623 ('74-later) is .830".
The INTERNET, the MISinformation superhighway
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Re: 727 Rear Clutch Upgrade worth it?
[Re: Hot 340]
#2418656
12/14/17 08:39 PM
12/14/17 08:39 PM
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Joined: Jun 2003
Posts: 52,972 Romeo MI
MR_P_BODY
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Master
Joined: Jun 2003
Posts: 52,972
Romeo MI
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Just picked one up. Casting number 3743623AB. Measures .782 thick. Maybe the "AB" is a revision? Most anytime you have letters following the numbers its been upgraded and on yours with a AB it was down a couple times
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Re: 727 Rear Clutch Upgrade worth it?
[Re: MR_P_BODY]
#2418704
12/14/17 09:51 PM
12/14/17 09:51 PM
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Joined: Dec 2006
Posts: 3,396 Pa
Hot 340
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Just picked one up. Casting number 3743623AB. Measures .782 thick. Maybe the "AB" is a revision? Most anytime you have letters following the numbers its been upgraded and on yours with a AB it was down a couple times 👍
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Re: 727 Rear Clutch Upgrade worth it?
[Re: Hot 340]
#2418798
12/15/17 12:53 AM
12/15/17 12:53 AM
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Joined: Mar 2011
Posts: 3,090 Michigan
A727Tflite
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Michigan
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I just saw your last photo. - yes - depending how you measure. Thickness is different - as long as you measure correctly using the machined register on the bottom of the piston ( the machined radial ridge ) to the top of the outer rim of the piston. EDIT- The way you are measuring in the last photo should show the different thicknesses between the two p/n's.
Last edited by Transman; 12/15/17 05:21 AM.
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Re: 727 Rear Clutch Upgrade worth it?
[Re: A727Tflite]
#2418809
12/15/17 01:16 AM
12/15/17 01:16 AM
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Joined: Dec 2006
Posts: 3,396 Pa
Hot 340
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part numbers 623 and 834
Last edited by Hot 340; 12/15/17 01:26 AM.
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