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Old 09-27-2016, 07:42 PM   #1
Eric1970
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Join Date: Apr 2012
Location: High Country, CO
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Muncie M21 (auto to manual un-conversion)

My 1970 longbed, step-side originally came with a 4-speed manual.
The previous owner installed a turbo 350, which I have now severely cracked.
I've been wanting to change it back to a four on the floor.

Does anyone have an idea of where I can find a remanufactured Muncie M21, preferably with a super case and mid iron plate?
(I've heard the super case and mid iron plate make it stronger;
Experience/opinions on this are welcome.

As I'm un-converting it, it is my understanding I'll need:
A bell housing
Flywheel (with number of teeth to match my starter)
A pressure plate
A clutch
Clutch fork, and a
Pilot bushing or bearing.

It was suggested I look for a donor truck to get the majority of the parts needed for un-converting it.

Fortunately, it looks like I'll have shop access to do the work.

Any ideas/insights into this project are most welcome.
This is the last moving part I need to replace.
After this, I can finally get to the body.

Thanks, all!
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Old 09-27-2016, 07:56 PM   #2
Ruscal
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Location: Carlsbad, California
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Re: Muncie M21 (auto to manual un-conversion)

Looks like you have it covered pretty well. You will also need a shifter and the clutch bellcrank and pedal parts. Some headers can interfere with the bellcrank. Hurst shifters work well on those boxes.
I just switched out a turbo 400 for a T56 magnum. Having overdrive is nice. In my install I went with a hydraulic clutch.
Russ
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Old 09-27-2016, 08:03 PM   #3
Grumpy old man
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Re: Muncie M21 (auto to manual un-conversion)

Not a problem , My Muncie guy rebuilds them for a living and can set it up anyway you want . Last count he had more than 150 in stock and he builds them for muscle car guys all over the country with a warranty . you can use a stock bell housing but it has to be from a 67 with the smaller trans hole if I remember correctly and I have those along with the clutch forks (stock) you should be able to use your current driveshaft and use your local auto parts store for the clutch/pressure plate and throw out bearing you can find clutch kits on ebay for $100.00 up depending on what HP your running . shifters are easy to find just not cheap for good ones , Do you still have your clutch pedal setup ? I have those also if you need it All the pieces are available all you need now is $.

See, Easy Peasy
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Old 09-27-2016, 09:55 PM   #4
jr1000yarder
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Re: Muncie M21 (auto to manual un-conversion)

Great info!!!

Grumpy, I'll be hitting you up when I get closer on my 67 build!
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Old 09-28-2016, 06:59 PM   #5
Eric1970
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Re: Muncie M21 (auto to manual un-conversion)

Grumpy,

What is your friends contact info?
Does he warranty his work?
May not need the super case and mid iron plate;
I've got to armor plate the underside, anyway;
The truck needs to be a mountain rod, as that's where it lives.

Another friend of mine thinks I ought to find an old blown up Vette and scavenge the five speed out of it, though for major parts, I'm looking for truly remanufactured with a warranty- not just rebuilt, I could do that myself.

Send me prices on the parts you have, and the zip you ship from, please.

Thank You!
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