I am converting my 70 Supreme to a M22 from auto.

I already own the M22.

I want a combo good for highway.

What would a M22 be like with 3.08?

Thanks in advance!

Chad
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An M-22 is a close ratio transmission. With 3:08 gears starting off will require some clutch slippage. An M-20 is more suitable with those gears. Both will have the same engine RPM's at cruising speed.

 

Thanks,

That's what I was afraid of, I'll just have to keep it at 55 on highway.

Chad

 

The final gear ratio is the same for the M22 and any 3 speed auto, its 1:1. So on the highway it will act the same as what you had.

 

The close ratio trans is a bad idea for street use anyway. Unless you must have the M22 for bragging rights, sell it for stupid money (since it's not original to your car anyway) and get something with a much wider spread from low to high. Assuming you want to stay with a four speed so you don't have to mess with tunnel mods, look for a Super T10 with the 2.88 first gear. That, in combination with a 3.08 rear gear will be very nice as an all around driver. Just FYI, my 70 W30 had a non-original 3.08 rear when I got it. Coupled with the M21 close ratio trans, it really sucked off the line.

 

Your problem is taking off from a stop. Like mentioned above, you would want an M-20. If what you have is a true M-22 then you could sell it for twice the price of what you could get an M-20 for.

 

As always, math is your friend. The 2.88 first gear in the Super T10 will make those 3.08s feel like 4.10 gears with the close ratio Muncie off the line.

2.88 x 3.08 = 8.87 effective final drive ratio in first gear with the ST10.
2.20 x 4.10 =9.02 effective final drive with the Muncie.

The difference is that in fourth, you've got 3.08 gears, not 4.10s.

 

Most M-22's came in Corvette's, Camaro's, or Chevelle's. It will be stamped with a partial vehicle serial number and the final assembly plant code. Someone may REALLY want that transmission. Do your research.

 

Well....

I live out in the middle of nowhere, it was difficult to find what I have.

I'm thinking 3.42 which looks to give me 55mph @ 2500RPM.

Thanks for the input!!

 

3.42s were just about the lowest numerically gears you could get from the factory with the close ratio Muncie. Still only a 7.52 effective final drive ratio in first, but better than the 6.78 you'd get with 3.08 gears. Rule of thumb is that you want to be around 9:1 in first.

 

Hi,

I have a M22W from Autogear, basically a new version of a Muncie with wide ratio gears similar to a M20 with the straighter cut gears like a rock crusher/M22

Autogear also makes a rod race version with a 2.98 first gear if memory serves and were designed to run a 3.08 gear as a option?

Regards

 

So just out of curiosity, does that M22W cost any less than a TKO five speed?

 

I had a Rallye 350 with a factory M-21 and 3.42 gears. It was about as tall as you would want to go. Even with 3.42 you have to slip the clutch a little for casual stop and go

 

Well that Is not good to hear considering the M22 has the 2.20 first gear......

 

Here's the latest price list, I can't complain about buying mine back in 2010, would be nice if it was a overdrive transmission

 

Here is the gear ratios

 

I had a m23 autogear in my 62 409 bel air,, worst shifting manual trans I had ever owned.

 

M22 and 308's and 13" tires.... would work tooooooooo

 

I agree with the others this would not be a good setup. You will burn your clutch up getting off the line.

My Rallye I am restoring has this combo, I changed the internals to go to a wide ratio.

Years ago I had a 70 Supreme 4 speed that came with a wide ratio and 3:23's. I changed it to a close ratio and 3:90's. I decided 3:90's suck on the street so I changed the rear to 3:42. That setup took a lot of clutch to get going, so I went back to the wide ratio.

Wide ratio and 3:42 is a nice setup, very quick off the line.

Good luck!

Pat


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Is there a 3.55 option?

It seems that there is only 3.42 or 3.9 and I think 4.11....

 

The options for a Type O axle in a 1970 are 3.42, 3.91. 4.33, 4.66, and 5.00

 

I'll also add that if you really do have a 3.42 ratio now, you'll need to change the carrier to use any lower numerical ratio. 3.23 / 3.42 is the carrier break point for these axles.

 

I still have the Super T10 I got in 1978, 9310 nickel gears, nodular main case, aluminum tail, 26 spline input and turbo 400 output, 2.88 first ratio. It was arguably the best/strongest Super T10 ever made. I had it in #24 before selling the car. In 1966, Olds published a guideline brochure telling people that they should get the wide ratio M20 unless the diff ratio was 3.91, iirc.

 

You're killen me Smalls

 

May well be saying what has been said already but I have some first hand experience with M22 & 3.08. I worked on a 67 SS with a whooped M21 that locked up & 4.11. I put him into an Autogear M22 which I found to be a great shifting, nice trans. Then he decided the 4.11 was intolerable driving to the beach between CT & RI. He opted for a 3.08. You really had to feather & ride the clutch with that setup, especially starting uphill even with a stout BBC, a far cry from the 4.11 sweetness.

 

I am now considering 3.5's

 

funny my car came with the m-20 and 3.08 posi ( 350 ) so if I look what Joe was saying and do the math 2.52 x 3.08= 7.7616 which seems a far cry from the recommended 9.1? but I don't recall this car having issues off the line or being a dog in first? I now have swapped in a 455 in I certainly don't want it to be a dog off the line? I thought about that when I put new clutches and bearings etc in maybe I should have upgraded the gear ratio? kicking myself a little now... I am not drag racing the car but would at least like to feel like a musclecar..LOL... and if possible beat my wife in her hemi rt Durango in the quarter mile ( 14.7 I believe )

 

Not with your current axle. Again, for the Type O, all you can get are 3.42, 3.91, 4.33, 4.66, or 5.00.

 

Since GM didn't have a four speed with a steeper first gear, so you got what you got. Again, that 9-ish:1 is a rule of thumb, not the law. Obviously it takes a little more clutch slippage, and there's the trade-off on not needing to shift into second quite as soon, which can help with ETs. Of course, the butt dyno is a notoriously inaccurate test instrument. Matching total gear ratio with engine HP and torque curves, including accounting for RPM drops when shifting, is what separates the successful drag racers from the losers.

 

Thanks Joe.
You are of course correct.
I think I am going to have go with the Ford 9" conversion...

 

Huh? Why would you do that?

 

"Talk me out of it please.

I can think of no better way of getting to 3.5's

I don't want to go tpo the trouble of converting the diff to 3.42 and hate it.
1000.00-ish for that or 2000.00 for the 9" plus I get disc brakes!!

 

not to mention having a couple of pumpkins on the shelf for all occasions a lot cheaper and easier to swap gears LOL....

 

Thanks Eddie for the encouragement!!

 

Okay.

1) The difference between 3.42 and 3.5 is so negligible as to be virtually undetectable on the street.
2) Unless you're going road racing, the difference rear discs will make will also be unnoticeable.
3) Why are you married to the M-22? As suggested above, sell it for a bundle of money to some guy who needs it for the correct restoration of a ZL-1, buy a Super T-10 with a 2.88 low and all your problems are solved. What's so hard?

 

Quit making so much sense!

I will test the market and see what I can get for the M-22

Thanks

 

sell your M-22. Buy a used Richmond / Nash 5 speed and keep your 3.08 gears.

 

Need bell housing too then?

 

You needed one for the M-22 or any other manual transmission so not understanding the question.

 

Sorry, I meant to ask if the bell housing for the M-22 would work with the 5 speed