I am just curious, do m-20's suck? Are they weak? Why are m-21's more popular?

Other than the gear ratios they are nearly identical. M21s were ( at least in 67 ) installed with 3.73 and higher numerical ratio and M20 for 3.55 and below. Therefore, the performance cars had the M21. I have one and I wish I had the M20 because I'd love the 2.52 1st gear. Regardless of what gear ratio I was running, the lower fist gear ratio would work my Drag radials better!

Saginaws "suck" for performance applications.

[This message has been edited by Gene Chas (edited 07-25-99).]

Remember that 'M20' was a sort of generic RPO code that simply meant 'Wide ratio 4-spd.' Within the same year same model, M20 could mean either Muncie or Saginaw, depending on which engine was in front. A Muncie M20 vs. an M21 gives the same strength tranny but with a different gear spread. The M22 is another story...
I know a guy that went through 6 Saginaw trannies because of his big right foot; yet I read about a guy racing a '74 Ventura GTO requiring a Saginaw to run in a stock drag class and he runs slicks. So far he's been winning & not breaking (sounds like the exception).

[This message has been edited by Cam (edited 07-25-99).]

Gene is exactly right, and no, they don't suck.

------------------
Tom H.
Member #259
www.iquest.net/~bharold/chevelle/ (http://www.iquest.net/~bharold/chevelle/)

I wouldn't want anything but an M20(Muncie). The 2.52 first gear, like others said, gets you off the line much better than the 2.20 first gear of the M21 or 22, especially with streetable rear gears. If you have a big block or torquer small block, you don't need the close ratio spread of the M21 or 22 anyway IMHO. von

I just swapped our my M21 for an M20 Muncie so I could rebuild the M21. For driving on the street the lower first gear of the M20 is definitely nicer to drive. The M21 and M22 have always had the racer image. My COPO Chevelle came with an M20 and the transmission gave excellent service.

Geez, maybe I should swap out my 21 for a 20 while the "illusion" of the 21 being better still exists!" Yeah sure I'll give you my 21 and I'll take your 20 and $300 bucks." Sounds like a deal made in heaven. http://www.chevelles.com/forum/smile.gif

Hey Gene, dont know if I read your post correctly but my 70 came from the factory in Canada with a M21 and a 331 rear end. Drives OK to me!

SKOTEEEEE,

My 70 also came from Canada w/ 3.31 but with an M20. What HP is yours rated at? Mine was an L34 396/350hp.

------------------
??michael Team Chevelle Gold #77
70 Chevelle SS396 Fathom Blue/White Stripes - Canadian built

Michael J
same as yours. Did you send for your options packet from GM of Canada? its really cool.Fathom blue w/white stripes also.

My 70 also had an M21 and 3.31 gears, but it was a small block, 300 horse 350. It was ok for normal driving but lacked a little in take off. Right now I would be happy with a saginaw over the the auto trans in my 64.

------------------
Philip Valentine
Team Chevelle Member #42 GOLD
philip@chevelles.com

Gentlemen, my '67 doens't have the original tranny, and SKOTEEEEE, I read that info somewhere ( probably here!). I still haven't ID'd the gear set in my car, but regardless, I would always prefer the 2.52 first. I believe I am running a M21 with 3.31 and it works OK. Letting out the cluch w/o gas ( or just a little) really bogs it down though. Plus I'd like a wider spread. The lower you go in gears, the close ratio gets too close. I can't imagine how it'd work with 411 or 56's. shift-shift-shift-shift, 35 mph. But I'm sticking with the 21 for now.

Never hit the stop button on the browser after you've hit "submit reply" it'll cause it to post twice.

[This message has been edited by Gene Chas (edited 07-28-99).]

I'm using an M-20 in my 69 with 4.56s. And it's true, it doesn't take long to wind out 1st gear. But it pulls like hell! I like it.