M-22 Upgrade
Thread Starter
Racer
Joined: Apr 2005
Posts: 494
Likes: 0
From: Virginia
M-22 Upgrade
Thinking about replacing the M-21 in my 73 – 350 with an M-22. There is nothing wrong with the M-21 and I would keep it. It’s a high performance engine, so the M-22 should be able to handle it better. Not sure what the gear ratio difference would be, but remember most cars that had an M-22 sounded great in the quarter mile. Also, it will probably add value to the car and make it more desirable, if I decide to sell it. Always liked that “Rock Crusher” sound. Am not interested in a 5-Speed, trying to keep the car somewhat of a period muscle car (60’s/70’s). 
Melting Slicks
Joined: Mar 2005
Posts: 2,838
Likes: 10
From: Austin TX
I have the Autogear Muncie M-22W (wide ratio) behind a 496 Camaro that makes some HP and torque. The Autogear stuff is quite a bit stronger than the old Muncies,..stronger box, stronger gears (from Maseo (sp?) in Italy,..high nickel, strongest out there and they're cut at the 'Rock-Crusher' angles for the strength and sound you're looking for), larger front bearing, cast-iron mid-plate, etc. Here's the link,..give them a call. Ask for George, Chief Engineer,..great guy. And don't run synthetics,..too slippery,..synchros don't functions as well.
http://www.autogear.net/
http://www.autogear.net/
Racer
Joined: Jan 2004
Posts: 428
Likes: 2
From: Everfrost Second Life
The importance of ratio spreads...
Something often over looked in regards to performance
The M22W ratio works very well with 3.55 and 3.73 rears. It's really not that wide of a ratio box and basically splits the difference between the early regular M20 wide ratio and the m21 close ratio. The new Autogear stuff is top shelf with very good reliability.
SORRY! Thanks Yeah I ran them in the opposite direction.... here is your revised data...
M20 2.52 1.88 1.46 1.00 - 25% 22% 31%
M21/ M22 2.20 1.64 1.28 1.00 - 25% 22% 22%
M22W 2.56 1.75 1.37 1.00 - 32% 22% 27%
M22X 2.20 1.51 1.17 1.00 - 32% 23% 15%
TKO600 2.87 1.89 1.28 1.00 .82 - 34% 32% 22% 18% (5th)
TKO500 3.27 1.97 1.34 1.00 .68 - 40% 32% 25% 32% (5th)
The M22W ratio works very well with 3.55 and 3.73 rears. It's really not that wide of a ratio box and basically splits the difference between the early regular M20 wide ratio and the m21 close ratio. The new Autogear stuff is top shelf with very good reliability.
M20 2.52 1.88 1.46 1.00 - 25% 22% 31%
M21/ M22 2.20 1.64 1.28 1.00 - 25% 22% 22%
M22W 2.56 1.75 1.37 1.00 - 32% 22% 27%
M22X 2.20 1.51 1.17 1.00 - 32% 23% 15%
TKO600 2.87 1.89 1.28 1.00 .82 - 34% 32% 22% 18% (5th)
TKO500 3.27 1.97 1.34 1.00 .68 - 40% 32% 25% 32% (5th)
Last edited by 5speeds; Jan 30, 2007 at 10:48 PM.
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Drifting
Joined: Jul 2002
Posts: 1,943
Likes: 1
From: Rosemount MN
If you want to turn your M-21 into an M-22 try these folks
http://stores.ebay.com/Zumbrota-Bear...QQftidZ2QQtZkm
I've used them for transmission parts, they have everything on hand and the prices are pretty good. They know their stuff and have heavy duty stuff available as well if you're racing.
http://stores.ebay.com/Zumbrota-Bear...QQftidZ2QQtZkm
I've used them for transmission parts, they have everything on hand and the prices are pretty good. They know their stuff and have heavy duty stuff available as well if you're racing.
Le Mans Master
Joined: Oct 2006
Posts: 7,123
Likes: 433
From: Gladstone MO
C3 of Year Finalist (appearance mods) 2019
The M-22 was at the beginning a 2.54 wide ratio box.
The biggest difference between the M-22 and the others was the gears were cut differently for a little more strength- and there's the noise too.
I've got a M-21 close ratio in mine (2.20 close ratio), and have never had any problems with it. Original engine was a 427/435, when it died it got a L-88 from the factory under warranty, and now it's a 454 with all LS-7 or ZL-1 parts inside. And 4:11's.
The biggest difference between the M-22 and the others was the gears were cut differently for a little more strength- and there's the noise too.
I've got a M-21 close ratio in mine (2.20 close ratio), and have never had any problems with it. Original engine was a 427/435, when it died it got a L-88 from the factory under warranty, and now it's a 454 with all LS-7 or ZL-1 parts inside. And 4:11's.
Racer
Joined: Jan 2004
Posts: 428
Likes: 2
From: Everfrost Second Life
Because the M20 and M21 use the same physical 1st , 2nd and 3rd gears you can see from the ratio drops that the spread is the same between 1-2 and 2-3 shifts. The WIDER difference lies in the 3-4 shift on the M20. However, by todays standards as compared to the TKO600 and TKO500 people no longer are concerned so much with close and wide ratio.
There is an article I wrote in regards to ratios AT THIS LINK
There is an article I wrote in regards to ratios AT THIS LINK
Racer
Joined: Jan 2004
Posts: 428
Likes: 2
From: Everfrost Second Life
The formula is (driven divided by drive) times (driven divided by drive).
Tooth counts are used to determine ratio
M20 1st gear example: head set - 25/21 x 1st 36/17 = 2.52
M21 1st gear example: head set - 27/26 x 1st 36/17 = 2.20
Le Mans Master
Joined: May 2006
Posts: 9,993
Likes: 1,136
From: League City Tx
All I know is that we have an original 1970 M22 out of an LS6 chevelle with the 2.20 low in our 59' with a ZZ4 and its a freakin dog in 1st gear. Even with the 4.11s in the rear, and a torquey ZZ4 in a 2900lb car, its still a dog. I would stick with your original tranny, I doubt its worth changing.
Racer
Joined: Jan 2004
Posts: 428
Likes: 2
From: Everfrost Second Life
All I know is that we have an original 1970 M22 out of an LS6 chevelle with the 2.20 low in our 59' with a ZZ4 and its a freakin dog in 1st gear. Even with the 4.11s in the rear, and a torquey ZZ4 in a 2900lb car, its still a dog. I would stick with your original tranny, I doubt its worth changing.
