Upgrade a Muncie?
Thread Starter
Burning Brakes
Joined: Oct 2006
Posts: 1,044
Likes: 0
From: Henrico VA
Upgrade a Muncie?
I have an original Muncie 4 speed transmission. I think I determined it was an M20. Anyways, I liked the idea of replacing the gear clusters of my first and third gears, so that my top speed in first gear goes from 50 to a little over 30 (maybe 30 at 5000 RPM). I like the idea of turning the 3rd and 4th gear lever upside-down and putting an overdrive in where third gear currently resides. I was thinking 0.67 would be a good ratio. As for first gear, I can do the math later and get a ratio. Does anyone know of anyone who makes or sells the clusters to upgrade the gears in a Muncie? I would have an expert on hand to walk me through this project which I think is very doable.
Race Director
Joined: Sep 2001
Posts: 10,560
Likes: 439
From: Wellington, FL
St. Jude Donor '11 thru '25
Get a hold of Paul here. http://www.5speeds.com/index.html
He was a big help to me when I rebuilt my Muncie.
He was a big help to me when I rebuilt my Muncie.
Thread Starter
Burning Brakes
Joined: Oct 2006
Posts: 1,044
Likes: 0
From: Henrico VA
Get a hold of Paul here. http://www.5speeds.com/index.html
He was a big help to me when I rebuilt my Muncie.
He was a big help to me when I rebuilt my Muncie.
Le Mans Master
Joined: Apr 2005
Posts: 6,355
Likes: 425
From: Seattle Area WA
Paul is good, you can also call Auto Gear directly, they make the super case and have the gears made.
http://www.autogear.net/
http://www.autogear.net/
Thread Starter
Burning Brakes
Joined: Oct 2006
Posts: 1,044
Likes: 0
From: Henrico VA
Paul is good, you can also call Auto Gear directly, they make the super case and have the gears made.
http://www.autogear.net/
http://www.autogear.net/
Le Mans Master
Joined: Apr 2007
Posts: 7,353
Likes: 72
From: Graceland in a Not Correctly Restored Stingray
The OD Muncie gearset is a complete close ratio set with a 0.87:1 (not 0.67) in place of the 1.27:1 3rd gear, resulting in the following steps: 2.20, 1.64, 1.00, 0.87. Since you're removing 3rd gear you'll essentially be stepping from 2nd to 4th, which is a pretty big change if you don't have a lot of torque (or even if you do). Also, that close ratio 1st (2.20) isn't suited all that well for FDR's taller than about 3.70:1 (smaller #'s).
If I had a pickup truck with a deep rear end, I might consider it, but after talking briefly with Paul on here about it I'm not so sure running around in 3rd in a sports car application is such a good idea anymore. FWIW, I've decided to rebuild my Muncie, which is ahead of a 3.55:1 FDR, with the M22 wide ratio gearset (2.52, 1,88, 1.47, 1.00). Just my $.02...
If I had a pickup truck with a deep rear end, I might consider it, but after talking briefly with Paul on here about it I'm not so sure running around in 3rd in a sports car application is such a good idea anymore. FWIW, I've decided to rebuild my Muncie, which is ahead of a 3.55:1 FDR, with the M22 wide ratio gearset (2.52, 1,88, 1.47, 1.00). Just my $.02...
Thread Starter
Burning Brakes
Joined: Oct 2006
Posts: 1,044
Likes: 0
From: Henrico VA
I hear you. I have enough torque to jump from 1st to 4th easily. Heck, I can start my car in 4th and run it comfortably under 20 mph uphill. I would like 4.00, 1.82, 1.00, 0.67. I think it work work well. Do you really see any issues with it?
The OD Muncie gearset is a complete close ratio set with a 0.87:1 (not 0.67) in place of the 1.27:1 3rd gear, resulting in the following steps: 2.20, 1.64, 1.00, 0.87. Since you're removing 3rd gear you'll essentially be stepping from 2nd to 4th, which is a pretty big change if you don't have a lot of torque (or even if you do). Also, that close ratio 1st (2.20) isn't suited all that well for FDR's taller than about 3.70:1 (smaller #'s).
If I had a pickup truck with a deep rear end, I might consider it, but after talking briefly with Paul on here about it I'm not so sure running around in 3rd in a sports car application is such a good idea anymore. FWIW, I've decided to rebuild my Muncie, which is ahead of a 3.55:1 FDR, with the M22 wide ratio gearset (2.52, 1,88, 1.47, 1.00). Just my $.02...
If I had a pickup truck with a deep rear end, I might consider it, but after talking briefly with Paul on here about it I'm not so sure running around in 3rd in a sports car application is such a good idea anymore. FWIW, I've decided to rebuild my Muncie, which is ahead of a 3.55:1 FDR, with the M22 wide ratio gearset (2.52, 1,88, 1.47, 1.00). Just my $.02...
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Le Mans Master
Joined: Apr 2007
Posts: 7,353
Likes: 72
From: Graceland in a Not Correctly Restored Stingray
Long ago I had a Super T-10 UltraWide, with 3.44:1 1st, that I got the bright idea to plunk into my C3. Multiply that times 3.55:1 FDR and the 12.212:1 was simply too deep, and as I quickly learned all I ended up doing was killing 0-60mph performance by pausing acceleration at pretty low speeds for what was really a premature shift. Wasn't fun to drive at all. IMHO, ~8-10:1 (1st x FDR) is really about as deep as you want to go, and the more bottom end torque you have, the smaller that ratio can be.
Thread Starter
Burning Brakes
Joined: Oct 2006
Posts: 1,044
Likes: 0
From: Henrico VA
I talked with AutoGear and they said that there isn't enough room in my Muncie box for what I want. He told me to get a 4.11 Diff if I want to go fast. It looks like I will need a new tranny no matter which route I take.
