Muncie Transmission Swap - The 1947 - Present Chevrolet & GMC Truck Message Board Network

magooster · 05-31-2005, 11:06 PM

I have a 65 GMC shortbox with a 3 on the tree and I am interested in putting in a Muncie 4 spd. Has anybody done this before? Could you let me know how it went with the clutch linkage and the crossmember etc.? Also what is the best model (M20, M21, or M22) to go with mated up to a 400 smallblock and a 3:73 12 bolt rearend? Thanks

speedking · 06-02-2005, 04:25 AM

I'm not real familiar with this combination firsthand,but a friend did the swap on his '64 Chevy. He had to get a special shifter to clear the seat (he said-I suspect he just wanted a Hurst shifter instead of the factory type).The clutch linkage is fine as is. Depending on how you drive and if you have the bellhousing rear engine mounts,you might not even need a crossmember for the transmission. It's possible your 3 speed already has a mount under it;if thats so,you might need to unbolt the crossmember from the frame and slide it back enough for the mount to match up to the 4 speed,then re-drill the mounting holes in the frame.I guess thats about all the rough spots. Everything else should be easy. I always wanted to try hooking a 4 speed up to the column linkage and run reverse off a separate lever or a cable.

bpmcgee · 06-02-2005, 01:38 PM

Speed,

You could always go with the SM420 -- Granny first 4 speed that was optional in your truck. That would be a pretty easy swap.

Brian

**special-K** · 06-20-2005, 10:35 PM

The Muncie 4spds will bolt right in place of the 3spds.

da-burb · 06-25-2005, 02:44 PM

Just read last night in one of Hemming's magazines that the M21 is a direct replacement for the 3spd manual or TH350. Same length and same spline count output so no driveshaft changes required. No first hand info though.

624whldr · 06-25-2005, 03:20 PM

65 3 spd was unsincro 1 st gear this made the trans shorter then the turbo 350 auto the m21 with a bell housing is a dirrect swap with the auto, not the 3spd you can use a mid 50s comp plus shifter and shorten the drive shaft youll be fine, also if the trans is from a camero the spdo drive ion the passenger side and you cable wont reach.
Ed

magooster · 06-27-2005, 07:51 PM

Thanks for all the info everybody. Now that I found all of that out, I'm also considering a Super T-10. any thoughts?

05-31-2005, 11:06 PM	#1
magooster '65 GMC Project Join Date: May 2005 Location: Abbotsford, BC Posts: 653	Muncie Transmission Swap I have a 65 GMC shortbox with a 3 on the tree and I am interested in putting in a Muncie 4 spd. Has anybody done this before? Could you let me know how it went with the clutch linkage and the crossmember etc.? Also what is the best model (M20, M21, or M22) to go with mated up to a 400 smallblock and a 3:73 12 bolt rearend? Thanks

06-02-2005, 04:25 AM	#2
speedking Registered User Join Date: Apr 2005 Location: Elko,Nevada,USA,Earth Posts: 78	I'm not real familiar with this combination firsthand,but a friend did the swap on his '64 Chevy. He had to get a special shifter to clear the seat (he said-I suspect he just wanted a Hurst shifter instead of the factory type).The clutch linkage is fine as is. Depending on how you drive and if you have the bellhousing rear engine mounts,you might not even need a crossmember for the transmission. It's possible your 3 speed already has a mount under it;if thats so,you might need to unbolt the crossmember from the frame and slide it back enough for the mount to match up to the 4 speed,then re-drill the mounting holes in the frame.I guess thats about all the rough spots. Everything else should be easy. I always wanted to try hooking a 4 speed up to the column linkage and run reverse off a separate lever or a cable. __________________ -57 GMC 1/2 ton longbed,Pont. 400,4 speed -62 Chevy 1 ton duallie,Chevy 355,4 speed -66 Pontiac Catalina 2 dr. hardtop,389,T-400 -81 Ford Fairmont wgn.,2.3,4 speed -68 Triumph TR6-R 'cycle,various mods -66 C-60's back -there's probably others...

06-20-2005, 10:35 PM	#4
special-K Special Order Join Date: Nov 2004 Location: Mt Airy, MD Posts: 85,863	The Muncie 4spds will bolt right in place of the 3spds. __________________ "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 ~

06-25-2005, 02:44 PM	#5
da-burb "Ochre Ogre" Join Date: Apr 2000 Location: Springfield, MN Posts: 3,558	Just read last night in one of Hemming's magazines that the M21 is a direct replacement for the 3spd manual or TH350. Same length and same spline count output so no driveshaft changes required. No first hand info though. __________________ Bowtie Truck Stop Inc. Mid-West GM Truck Restoration Parts Supplier Your Key Parts, Auto Metal Direct, Dynacorn, and Goodmark dealer. like us @ www.facebook.com/BowtieTruckStop 1971 C-10 Suburban (Ochre) 1971 K-10 Suburban (Ochre) 1972 C-10 Suburban (Ochre) 1972 K-20 Suburban (Yellow- that just aint right!) Springfield, Minnesota 56087

06-25-2005, 03:20 PM	#6
624whldr drive it not trailer it Join Date: Feb 2005 Location: So Jersey Posts: 64	drive shafts is gonna be to long 65 3 spd was unsincro 1 st gear this made the trans shorter then the turbo 350 auto the m21 with a bell housing is a dirrect swap with the auto, not the 3spd you can use a mid 50s comp plus shifter and shorten the drive shaft youll be fine, also if the trans is from a camero the spdo drive ion the passenger side and you cable wont reach. Ed

06-02-2005, 01:38 PM	#3
bpmcgee Registered User Join Date: Mar 2003 Location: Northern Illinois Posts: 2,181	Speed, You could always go with the SM420 -- Granny first 4 speed that was optional in your truck. That would be a pretty easy swap. Brian

06-27-2005, 07:51 PM	#7
magooster '65 GMC Project Join Date: May 2005 Location: Abbotsford, BC Posts: 653	Thanks for all the info everybody. Now that I found all of that out, I'm also considering a Super T-10. any thoughts?



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