Muncie
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Instructor
Joined: Apr 2021
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Muncie
I bought a 1964 Muncie m20 to go into my 73 vette. My brother has a 76 vette and put a later Muncie like a 74 Muncie into it without having to change the driveshaft or anything. I thought I read somewhere that my 64 Muncie wont be the same length and match up as my turbo 400 did, does anyone know if this is true or am I going to need a longer driveshaft or??
Le Mans Master
Joined: Mar 2004
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From: Little Rock AR
The driveshaft yoke on the '64 Muncie will be smaller than your existing TH400 yoke. The shifter assembly will probably need to be for a '68. That is the only year C3 that shifter linkage will interchange. The '64 Muncie should have the larger iron front bearing retainer so that helps. '63 is a smaller aluminum retainer.
Hope it has the right tailshaft housing. Speedo outlet sides are different on other GM brands.
That's a start.
My best advise is to stop now and get the right transmission for your year of car. That way you can avoid the struggle, pain and cost of building a mongrell. The right stuff will fit and function properly.
Hope it has the right tailshaft housing. Speedo outlet sides are different on other GM brands.
That's a start.
My best advise is to stop now and get the right transmission for your year of car. That way you can avoid the struggle, pain and cost of building a mongrell. The right stuff will fit and function properly.
Is my vette stock?? HAHA
Joined: Oct 2015
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From: Im not allowed to tell you
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I believe the 400 is wider and longer than a th350. Other than that you can use the M20. I have had all sorts of years and they are all the same provided they were for the corvette. SO it will fit but the driveshaft may be to short and the splines on the output shaft are going to be different. Auto to manual is never really plug and play, theres always something
Thread Starter
Instructor
Joined: Apr 2021
Posts: 133
Likes: 5
The driveshaft yoke on the '64 Muncie will be smaller than your existing TH400 yoke. The shifter assembly will probably need to be for a '68. That is the only year C3 that shifter linkage will interchange. The '64 Muncie should have the larger iron front bearing retainer so that helps. '63 is a smaller aluminum retainer.
Hope it has the right tailshaft housing. Speedo outlet sides are different on other GM brands.
That's a start.
My best advise is to stop now and get the right transmission for your year of car. That way you can avoid the struggle, pain and cost of building a mongrell. The right stuff will fit and function properly.
Hope it has the right tailshaft housing. Speedo outlet sides are different on other GM brands.
That's a start.
My best advise is to stop now and get the right transmission for your year of car. That way you can avoid the struggle, pain and cost of building a mongrell. The right stuff will fit and function properly.
Last edited by 1973bluevettee; Dec 12, 2021 at 02:48 AM.
Melting Slicks
Joined: Jun 2006
Posts: 2,071
Likes: 147
From: S Nevada
There are several differences between a 64 Muncie and the later muncie transmissions. GM kept updating the transmission, ie, more splines on the input and output shafts for strength, also larger diameter, stronger mid case castings. Physically the trans should fit just fine in your 73. But, if you want to put any power to it, it may be in your best interests to buy a later model transmission. Food for thought. I have my 72 m20 in a box that my tremec tko 600 came in. Personally, I like the 5th od gear. But that original muncie is a pretty nice transmission.
Is my vette stock?? HAHA
Joined: Oct 2015
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From: Im not allowed to tell you
2020 C3 of the Year Finalist - Modified
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run it
Thread Starter
Instructor
Joined: Apr 2021
Posts: 133
Likes: 5
There are several differences between a 64 Muncie and the later muncie transmissions. GM kept updating the transmission, ie, more splines on the input and output shafts for strength, also larger diameter, stronger mid case castings. Physically the trans should fit just fine in your 73. But, if you want to put any power to it, it may be in your best interests to buy a later model transmission. Food for thought. I have my 72 m20 in a box that my tremec tko 600 came in. Personally, I like the 5th od gear. But that original muncie is a pretty nice transmission.
Tech Contributor
Joined: Aug 1999
Posts: 15,135
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From: Connecticut, USA
The early Muncies speedo was on the Drivers side, then moved to the passenger so you see if that will be a problem. The 64 has a 7/8 cluster shaft where the later ones, starting 67 if I recall were 1". Diff input spline count so make sure you have the right clutch. Pop the side cover and take a look inside before installing. Check the front of the case at the cluster shaft for oil leaks. Check the slop yoke for grooves.
Muncies aren't a bad street trans but if you start hammering on them with power you will break them.
Muncies aren't a bad street trans but if you start hammering on them with power you will break them.
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Is my vette stock?? HAHA
Joined: Oct 2015
Posts: 20,111
Likes: 9,239
From: Im not allowed to tell you
2020 C3 of the Year Finalist - Modified
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