Does anybody know anything about the muncie 4 speed overdrive tranny,I want to replace my saginaw 3 speed.

I am not going to say that one does not exist but as far as I know, the original Muncie Series 4 speed transmissions have a 1:1 ratio in 4th gear.

There is really no such ting but you can put a Gearvenders OD Unit on the back of a Muncie - needless to say - it's expensive.

Check out Bill's site. fourth gear is .87:1 I got one of his rebuilt transmissions 8 years ago and it is still running strong. The overdrive gear was not available at the time but he can swap it out for you.

http://www.m-22.com/m22/

Brandan-

I have seen them for sale from classic industries,muncie m21y for about 1800.00

check out the new process four speeds that came behind 2WD chevy trucks in the early 80's (if i remember right). not the easiest thing to find but cheaper that something like a gear vendors unit or TKO if you want overdrive.

Does anybody know anything about the muncie 4 speed overdrive tranny,I want to replace my saginaw 3 speed.

Yes, there is a Muncie overdrive gearset from Autogear. What would you like to know about it?

or another option is to look for a standar, non overdrive 4-speed with a deep first gear and run some highway gears in the axle with tall tires. didn't saginaws go up to something like 3.50 first? still easy off the line but low RPM's going down the highway.

Its going behind a300 horse 327 I would like to know how reliable,how much longer than my saginaw,and if I am going to have to cut my trans tunnel?

or another option is to look for a standar, non overdrive 4-speed with a deep first gear and run some highway gears in the axle with tall tires. didn't saginaws go up to something like 3.50 first? still easy off the line but low RPM's going down the highway.

Great statement and I agree that this driveline engineering is much better. The overdrive gearset was designed for the person who may have rebuilt their differential but wants a little more top end cruising.

The new Muncie 4 speed gearset's have a first gear ratio of: 2.20:1, 2.56:1, & 2.98:1

These three listed gearset's were designed to be used with a differential ratio of:
2.20:1 (M22 & M21) - 4.10:1
2.56:1 (M22W & M20) - 3.55:1
2.98:1 (M22Z) - 3.08:1

Note: these combinations are not set in stone, just basic guidelines.

Its going behind a300 horse 327 I would like to know how reliable,how much longer than my saginaw,and if I am going to have to cut my trans tunnel?

The overdrive Autogear Muncie gearset is basically an M21 with an overdrive gear. The gearset is very reliable and will survive behind a 300hp 327.

A Muncie 4 speed can be configured for a perfect replacement of a Saginaw transmission and no tunnel mods needed.

It also depends on your differential gearing what transmission gearset would works best.

What is your differential gearing?

If you are going thru this much trouble , looking for a deep first gear trans, why not go TKO 500. Has 3.27 first and still has the OD gear.

I believe I have 3.08s,the saginaw is great around town,sucks on interstate cruising.The tko is more than I can afford,I have access to a m21 with hurst shifter,needs rebuilding.

What do you mean when you say "sucks on interstate cruising"? Since you're looking for an overdrive, I'm assuming you want less RPM/noise? With 3.08 rear gears and a 1:1 top gear (3rd) on the Saginaw, you should be at something like 2600 RPM at 65mph (does that sound right?)

Your current Saginaw should have a 2.54 1st gear and a 1.00 3rd gear, so you have a ratio spread of 2.54 (lowest gear divided by highest gear). With 3.08's, you'd have a 7.82 overall 1st gear and a 3.08 overall top gear.

The problem I see with the overdrive Muncie gearset is that it has nearly the EXACT ratio spread that you have now. 2.2 1st gear and 0.86 4th = 2.56 ratio spread. IF you keep the 3.08's, that would put you at a 6.78 overall 1st gear and a 2.65 overall top gear ratio, which would drop the revs to ~2250 in 4th at 65mph. BUT that 6.78 overall 1st gear will hurt performance around town... especially with a 3.27

So let's say we change the rear to a 3.55 to get the performance back. That would put you at 7.81 overall 1st gear and 3.05 overall top gear ratios... Hmmm, that's right back where you started....

Alternatively, if you just kept the 3-speed and changed the rear to a 2.73 ratio, you'd have a 6.93 overall 1st and a 2.73 overall top gear for about 2300 RPM at 65mph....

Basically, since the overdrive gear set has nearly the same ratio spread as your current setup, you're just going to sacrifice low-end performance for highway revs (albeit with an "extra" gear in between and closer ratio spacing). To get the best of both worlds, you really need something with a wider ratio spread. Yeah, you could drop the $$$ on something like a TKO600 with a spread of 2.87/0.64 == 4.48, but cheaper would be to pick up a Super T-10 "wide-ratio" setup with the 3.42 1st and 1:1 4th gear (3.42 spread). Change the rear to 2.73's and you'd have a deep 9.33 overall 1st and 2.73 overall 4th. Heck, you could even put in 2.56's and get 8.75 1st and 2.56 4th ratios.

I had this setup in my '69 for a couple years behind a 307 and for a street car, it's great -- good 1st gear launch and keep the rev's down on the highway. Super T10 is NOT the strongest trans in the world, but behind a 327, it should be quite happy....

For those of you playing along at home, good Super T10 info is here:
http://fiedlerh.home.att.net/BW.htm

I believe I have 3.08s,the saginaw is great around town,sucks on interstate cruising.The tko is more than I can afford,I have access to a m21 with hurst shifter,needs rebuilding.

To utilize any transmission AND if you want the best for your car, you cannot guess or assume your differential gearing, you MUST know the excact ratio so you are happy in the end.

If you do have a 3.08:1 differential gearing and do not like the 4th gear cruising, you surely won't like an OD transmission.

Re-read this "quote" below............

What do you mean when you say "sucks on interstate cruising"? Since you're looking for an overdrive, I'm assuming you want less RPM/noise? With 3.08 rear gears and a 1:1 top gear (3rd) on the Saginaw, you should be at something like 2600 RPM at 65mph (does that sound right?)

Your current Saginaw should have a 2.54 1st gear and a 1.00 3rd gear, so you have a ratio spread of 2.54 (lowest gear divided by highest gear). With 3.08's, you'd have a 7.82 overall 1st gear and a 3.08 overall top gear.

The problem I see with the overdrive Muncie gearset is that it has nearly the EXACT ratio spread that you have now. 2.2 1st gear and 0.86 4th = 2.56 ratio spread. IF you keep the 3.08's, that would put you at a 6.78 overall 1st gear and a 2.65 overall top gear ratio, which would drop the revs to ~2250 in 4th at 65mph. BUT that 6.78 overall 1st gear will hurt performance around town... especially with a 3.27

So let's say we change the rear to a 3.55 to get the performance back. That would put you at 7.81 overall 1st gear and 3.05 overall top gear ratios... Hmmm, that's right back where you started....

Alternatively, if you just kept the 3-speed and changed the rear to a 2.73 ratio, you'd have a 6.93 overall 1st and a 2.73 overall top gear for about 2300 RPM at 65mph....

Basically, since the overdrive gear set has nearly the same ratio spread as your current setup, you're just going to sacrifice low-end performance for highway revs (albeit with an "extra" gear in between and closer ratio spacing). To get the best of both worlds, you really need something with a wider ratio spread. Yeah, you could drop the $$$ on something like a TKO600 with a spread of 2.87/0.64 == 4.48, but cheaper would be to pick up a Super T-10 "wide-ratio" setup with the 3.42 1st and 1:1 4th gear (3.42 spread). Change the rear to 2.73's and you'd have a deep 9.33 overall 1st and 2.73 overall 4th. Heck, you could even put in 2.56's and get 8.75 1st and 2.56 4th ratios.

I had this setup in my '69 for a couple years behind a 307 and for a street car, it's great -- good 1st gear launch and keep the rev's down on the highway. Super T10 is NOT the strongest trans in the world, but behind a 327, it should be quite happy....

For those of you playing along at home, good Super T10 info is here:
http://fiedlerh.home.att.net/BW.htm

A lot of excellent thought went into this post......

3.08s cruise fine at highway speeds, IMO, and it was perfectly normal to run down the highway at 70-75 mph @ 3000 rpm in the 1960s. No one would have given it a second thought. I think our perception of what is acceptable has changed, since everything built in the last 25 years has an OD trans. You will not hurt the 327 spinning it at 3000 rpm for hours on the highway, and if it is a mild build, it should still have no problems pulling down 17-20 mpg at these speeds.

(PS: I just did a 400 mile round-trip 2 weeks ago with my 327, 3.08 gear combo. 18 mpg, running at 3200 rpm on the PA turnpike. :) )

Hey JodysTransmissions what is the price on the conversion kit for the overdrive for the m21 trans? I have a extra m21 and wondering about changing it out. How much RPM reduction will this kit do for 4th gear? Wanting to go for a 1 or 2 week drive WEST next year. I have bought a 3.08 non posi 1967 rearend allready and looking at all options. My current rear is a 3.55 posi . The non posi will stay cooler for trip and lower RPM. Have had a rear hitch built for car too for pulling small trailor.
:popcorn::popcorn:

That 2.20 first will be a clutch killer w/ 3.08s, IMO. I don't think this gearset is AT ALL suited for anything less than 3.73 or deeper gears. Maybe Jody can give his opinion?

My car is mostly original,a cruiser no racing,occasional tire spin.We drive to cruisin the coast every year (275 miles)and I do get about 18mpg. would like a little more mpg,less rpm at 70(speed limit in alabama on the interstate).The criuse ins and shows are usually 15-20 miles from home.We drive the car 2-3 times a week.Again not a hotrod just a cruiser.

If I were already getting 18MPG I wouldn't do anything.
Thats pretty good mileage for a performance car.

I have 3.55 gears and would not recommend a m21 for these. The 3.08 gear rear is only for cross country drive. I have my rear end set up to be able to change easily. last time i changed from the 456 rearend it took 2.5 hours and i was bleeding brakes. I have solid motor mounts and i take the crossmember out and replace trans within 2 hours not touching exhaust either. So parts changing is not a real big issue with me. Just wanting to no if that muncie trans kit is reasonable and to have it setup ready to go for any siduation or drive that may come up. Also i agree about the 18MPG Don't touch it. Best i ever got was 12 MPG

Hey JodysTransmissions what is the price on the conversion kit for the overdrive for the m21 trans? I have a extra m21 and wondering about changing it out. How much RPM reduction will this kit do for 4th gear? Wanting to go for a 1 or 2 week drive WEST next year. I have bought a 3.08 non posi 1967 rearend allready and looking at all options. My current rear is a 3.55 posi . The non posi will stay cooler for trip and lower RPM. Have had a rear hitch built for car too for pulling small trailor.
:popcorn::popcorn:

Charlie,

The OD kit is roughly $500.00 to convert an M21 to an M22Y. Multiply .859 to any known figure/spec to see the results of this gearset.

3.55:1 x .859 = 3.05:1 final drive
3000 RPM x .859 = 2577 RPM

Why not install a 2.73:1 differential using an M22Z gearset with a 2.98:1 1st. This combo would have a 1st gear takeoff feel of an M21 with a 3.70:1 differential. But, a final drive of a 2.73:1. One driveline set-up to cover your short and long distant trips.

Why not install a 2.73:1 differential using an M22Z gearset with a 2.98:1 1st. This combo would have a 1st gear takeoff feel of an M21 with a 3.70:1 differential. But, a final drive of a 2.73:1. One driveline set-up to cover your short and long distant trips.

Heck, if he's already got a 3.08 (and it's in good shape) just use it with the M22Z gearset. End up with even better off-the-line performance than he has with the 3.55's and the same highway revs as the 3.08's. Transfer the Posi setup from the 3.55 rear end and sell off your (now spare) rear...

Ratio spread == good *

*(as long as your engine can take a little more RPM drop between shifts -- really peaky engines that make "all" of their power at high revs don't like wide ratios...)

Thinking about the differences i am more convinced that the M22Z would be more beneficial. I could use it for both rearends. The overdrive with the 3.08 might be to low on the power range of engine. Stock 520 lift cam.
And then say 3.08 works great all around and then like yous said i could sell the 3.55 rearend complete. And i still have the original 456 rearend in the garage under the bench. And will have the current M21 for that rearend lets say. What all comes in the kit?

The complete M22Z gearset is roughly $800.00.

Using a 3.08:1 differential with the M22Z will have the same 1st gear take-off feel as using an M21 and a 4.17:1 differential.

[I]I am comparing all the ratio's out for what i have now. Third gear for me was important for my driving on secondary roads. It works out to be the same as i have now with the 355 and M21 vs 308 and M22Z. Right?

[I]I am comparing all the ratio's out for what i have now. Third gear for me was important for my driving on secondary roads. It works out to be the same as i have now with the 355 and M21 vs 308 and M22Z. Right?

Yup --
M21 ratios are: 2.20 / 1.64 / 1.28 / 1.00
With a 3.08 rear, that'd put you're overall ratios at: 6.78 / 5.05 / 3.94 / 3.08
With a 3.55 rear, that'd put you're overall ratios at: 7.81 / 5.82 / 4.54 / 3.55

M22Z is the "super wide ratio" gearset with: 2.98 / 2.04 / 1.47 / 1.00
With a 3.08 rear, that'd be: 9.18 / 6.26 / 4.53 / 3.08

You end up with about the same 3rd gear overall as you have now with the 3.55's, same 4th gear overall as you have with the 3.08's and a deeper 1st/2nd than you have with either.

I pulled the 456 rearend out and replaced with a 355 rearend and could tell with the speed that 3rd was actually my old 4th gear. So it was like gaining another gear for driving. Looking at ratio's now shows this to be true. Thats why my 3rd gear is good for side roads. this is funny seeing this:hurray:The only draw back was the low speed city driving,people driving automatic cars, Still drives me crazy but i deal with it.

Looking at the kits, are the input shafts all fine spline?

All M22 style gearsets are available in 10 or 26 spline configurations.

Wonder if we could organize a group purchase package on the M22Z Gearsets? ;)

Wonder if we could organize a group purchase package on the M22Z Gearsets? ;)

I can do group purchase or maybe a combined group purchase on any style complete gearset purchased.

I would consider the possibility
Alot of hits on this thread too

I was going to wait until spring to gather parts for my build, but if there is enough interest to get this going, and there is some savings there, I could be in for a M22Z w/ 26-spline input. :)

I'm glad I found this post. Now I just hope some of you are still around to help. I have a '69 with a 388 cubic inch stroker making 503hp and 517 lb/ft of tq. I currently have a stock M20 that sounds like it's about to lose 4th gear and a 12 bolt posi with 3:73's. I'd like a better final drive ratio of around 3:08 or even 2:73's. I still like a low first gear but with a really flat tourqe curve (engine dyno sheet shows over 425 lb/ft at 2000 rpm's) I know I don't need the 3:73's. Anyway I was looking into the gear vendors unit when I stumbled onto this topic. What would be the best muncie (M22Z, M21Y)/rear end combo for my application?

Very good info.

I'm glad I found this post. Now I just hope some of you are still around to help. I have a '69 with a 388 cubic inch stroker making 503hp and 517 lb/ft of tq. I currently have a stock M20 that sounds like it's about to lose 4th gear and a 12 bolt posi with 3:73's. I'd like a better final drive ratio of around 3:08 or even 2:73's. I still like a low first gear but with a really flat tourqe curve (engine dyno sheet shows over 425 lb/ft at 2000 rpm's) I know I don't need the 3:73's. Anyway I was looking into the gear vendors unit when I stumbled onto this topic. What would be the best muncie (M22Z, M21Y)/rear end combo for my application?

How do you plan on using the car? Street only? Drag race? Slicks or race tires ever? Do you do much highway driving or just around town?

If you're looking for lower revs on the highway while still keeping the car fun, I'd strongly recommend looking into a TKO600 5-speed and keeping the 3.73's. With the torque you're running, I don't think I'd want to run the "super-wide" muncie gearset and with only 4 speeds, you're going to have to compromise between around-town performance and highway revs....

Anyone else have feedback suggestions for 3supersports? I have virtually the same set up but running a th350 and want to convert to manual. Id love a tko or rs600 but don't have 4k for a kit so I have been looking into rebuilt muncies but am confused as to which gearset I should look for. Thanks for your suggestions.

Hey Scott this is a great thread. Not to hi-jack it, but I figured I would ask a question here since it is a simular question. I have a 342 read end gear and I am looking at building a small block as well. However I am wondering what would be the best trans to go with. I want to drive a stick. I am partial to the M22, but want to make sure that that is the best application for the street. Obviously like everyone else, hiway is a concern but where I will be doing the least amount of driving.

What are we looking at $ for a 5 or 6 speed manual trans?

I am looking for half decent hiway performance, but also a the best possible off the line performance. Something that will allow me to haze the tires with a small block that will put out around 400HP.

You do realize this thread was started in 2009 and last response was over a year ago.;)

So?

Is it still not a relevant question or topic?

I'd still appreciate some input.

Thanks

Here is some updated info: the M21Y OD gearset from Autogear has been discountinued. The OD gearset might be reborn with an M22 style helix angle gearset if there is enough interest.........