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#1 |
Registered User
Join Date: Nov 2014
Location: Kelowna, British Columbia
Posts: 9
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Muncie 4 speed swap
Over the past few months I've been gathering everything I need to convert my 357/th350 combo over to a 4 speed muncie
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#2 | |
The Older Generation
![]() ![]() ![]() Join Date: Aug 2006
Location: Montezuma, Iowa
Posts: 25,483
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Re: Muncie 4 speed swap
Quote:
I'm not sure about the 12".... I put an 11" out of an Astro Van in my '67 when I put the S-10 5 speed in it. There is a lot of reading in the thread I posted the link to below, but you may find your answer there.... http://67-72chevytrucks.com/vboard/s...d.php?t=313954 LockDoc
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Leon Locksmith, Specializing In Antique Trucks, Automobiles, & Motorcycles (My Dually Pickup Project Thread) http://67-72chevytrucks.com/vboard/s...d.php?t=829820 - |
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#3 |
Registered User
Join Date: Apr 2013
Location: South Westerlo, New York
Posts: 1,325
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Re: Muncie 4 speed swap
Don't forget the pilot bushing..
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Thanks, Joe.. 1969 C/10, 348 C.I., 3X2 bbl. V8, 2004r , LWB. |
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#4 |
Senior Member
![]() Join Date: Feb 2002
Location: Tucson, AZ USA
Posts: 7,260
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Re: Muncie 4 speed swap
I haven't done it myself but I think the 12'' clutch works in the bellhousing for the SM465 Muncie. I have an 11'' clutch behind an L6 292 in a '68 C/10. And (I think 11") in a '71 GMC Jimmy [4x4] 350/SM465/NP205/3.73 Posi. The 12'' was optional [for SBCs], but can't say the whys and wherefores.
You will need a flywheel for a 12''.
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Every 25 years I like to rebuild that 292, whether it needs it or not. |
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#5 |
Registered User
Join Date: Nov 2014
Location: Kelowna, British Columbia
Posts: 9
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Re: Muncie 4 speed swap
I have a 12" flywheel for it but I'll have to see if it works! The Trans I got is actually a m21 from a guy out here in Canada and have a chevelle bellhousing he told me it can fit an 11" but I'm not sure if 12 will do? Will a sm bellhousing work on a m21?
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#6 |
Registered User
Join Date: Jan 2013
Location: Eastern TN
Posts: 1,921
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Re: Muncie 4 speed swap
12" clutch will fit fine as long as the bellhousing will accept it. Most trucks I have seen had the larger version of the bellhousing. The smaller clutch housings where usually on cars or I6s. They are pretty obvious as they don't look like a 1/4 of a circle. Instead they slope done quickly towards the trans mounting bolts.
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#7 |
Senior Member
![]() Join Date: Feb 2002
Location: Tucson, AZ USA
Posts: 7,260
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Re: Muncie 4 speed swap
The bellhousing for the SM465 has the casting number [GM5]3925505 with a 5-1/8" I.D.
The SM420 bellhousing has casting: [GM11]3815891 w/4-9/16'' I.D.
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Every 25 years I like to rebuild that 292, whether it needs it or not. Last edited by '68OrangeSunshine; 03-25-2015 at 11:41 PM. |
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#8 |
Registered User
Join Date: Apr 2000
Location: Leesburg, GA
Posts: 746
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Re: Muncie 4 speed swap
One thing you may also want to consider is that a borg & beck clutch is going to have a higher pedal pressure than a Diaphragm clutch. Had both styles in a 69 Camaro, back in the day, and the diaphragm clutch was much easier on my left leg in traffic than the borg & beck.
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FOUNDING MEMBER OF THE DRUM BRAKE CLUB Second Owner 70 C-10 Second Owner 93 GMC C1500 Third Owner 99 C2500 Crew Cab Short Bed |
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