thinking of one I saw. Any info

Don't know what info you are looking for but here goes. A few years ago the TH250 in my car crapped out so I decided to switch over to manual. Found this 1970 M20 on Yahoo auctions and paid about $300 for it. Guy said that it was in good working order, only found out later that the bearings are worn out making the transmission rather loud in 1st - 3rd. However, since I didn't (and still don't really)have the money to rebuild it I am still driving on it and after a few thousand miles the thing is still going. I have even recently driven it all the way from Tallahassee, FL to Houston, TX without incident.

Now the gear ratio is a little off for the rear-end set up that came with my car. The rear-end is a 2.73 so I have no real acceleration off the line, but I don't reach 3000 rpm until somewhere near 85 mph, so it is perfect for the long haul. But something closer to a 3.11 or 3.31 would probably give a better start. I myself may just put a 3.08 in when I start my overhaul of the car.

The muncies are rather strong transmissions although I have read that the M21 or 22 would be a little better for high torque engines.

I know that there have been some posts in this section that deal with the in's and out's of these transmission.. you might try a search.

Hope this helps.

Be careful with the gear ratios.

I have a stock M20 in my '83 C10 and the first gear ratio is 6.55:1

Not something you want to run in a Camaro. http://www.nastyz28.com/ubb/wink.gif

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350CID, Vortec 062 heads, Magnum 280, Performer Intake, Holley 650 DP, 3.42 rear w/ Auburn posi, 2600 Stall/TC

[This message has been edited by AJ_72 (edited November 21, 2003).]

<font face="Arial,Verdana" size="2">Originally posted by AJ_72:
Be careful with the gear ratios.

I have a stock M20 in my '83 C10 and the first gear ratio is 6.55:1

Not something you want to run in a Camaro. http://www.nastyz28.com/ubb/wink.gif
</font>


The Muncie truck tranny with the granny first gear isn't even related to the Muncie M20 that went into the cars. The truck tranny is often listed as RPO M20 for trucks, but it is the model 465 tranny, which is a tranny with internal shifter, cast iron case, non-syncronized first gear and about 2:1 jump between gears.

The real M20 which went into performance cars has external shifter, aluminum case, 4 syncronized gears, and about 1.25:1 ratio between gears.

Two entirely different trannys for two entirely different purposes.

the one Im looking at the guy said it has a 2.54 first gear if I remeber right

Automotive M20 does have a 2.54 1st gear. Should have 2 rings cut around input shaft grooves. Good tranny, same basic design as M21, just has lower torque rating due to greater torque multiplication of the 2.5 vs 2.2 1st of M21.

Yes, the car M20 has either 2.56 or 2.52 first gear depending on year.

Read all about them here:

http://www.nastyz28.com/2gcog/stegmiller/muncietxt.htm


[This message has been edited by Gary S (edited November 22, 2003).]

thats what it was a 2.52 first. ebay has a buy it now option for 595.00 he says he will ship for 30$ I think it says its a 68 casting. good deal? he says its rebuilt and has 838 miles on it