Old 04-13-2008, 10:56 AM
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A friend of mine is converting a '67 Firebird from an auto trans to a 4 speed. He is in the process of rounding up all the necessary parts. He is going to look at a trans on Wed and wants to know how to identify a Muncie from a Saginaw or a B/W T-10.

I told him the Muncie would be all aluminum, but beyond that I don't have anymore advice.

I think some Muncies have a groove machined into the input shaft to denote a wide ratio from a close ratio, but I'm not certain of that.
Anyway, I know some guys on this site can help me help him.

How do you distinguish a Muncie from the others, and how can you tell a M-21 from a M-22? And any other advise you can offer.
Which would be better in a street driven, almost stock Firebird with 2.73: gears in it.

Thanks in advance for your help.
jugheadflanders is offline  
Old 04-13-2008, 02:52 PM
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muncie has 7 bolts in the side cover the BW had 9 and as you said the saginaw was iron.

there is a web page somewhere with a bunch of info on identification of them...I have seen it posted on another forum before...might do a google search.
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Old 04-13-2008, 04:06 PM
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I have a Richmond T-10 in my 66 Impala.Weighs right at 4200.Got a 2.73 gear in it.My first gear ratio is right at 2.89 I believe.The deepest I could find.Motor makes 385 horsepower and a little mote torque.Car is real peppy to be geared so high and heavy.I love it.Been abusing (seriuosly)that tranny since I bought it new 43,000 miles ago.Not one hiccup.Knock on wood.
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Old 04-13-2008, 04:54 PM
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The M22 Munci has a fine spline input shaft and the output shaft is the same size as the T400. The M21 have the coarse spline and the output shaft is the same a T350/powerglide. The double rings on the input shaft usually indicated a close ratio. I had a single ring which had the lower 1st gear ratio which made it nice for the heavier car.

Most of the M22's have the straight cut gears and would be a little noisy for the street, but I do know that in 1973 the Corvette had a fine spline input and T400 output with the heli-cut gears. I purchased it from the owner of the Vette when he went to a Doug Nash 5-speed. That was the best Muncie that I ever owned and when I purchased it, it was in pieces and several buckets.

Stay far away from the Saginaw, because they are super weak. The T-10's are good and I think that there was 1 version that even came in an aluminum case.

I would recommend a steel flywheel and a shatterproof, if you can. I had a flywheel explode on me once and luckily I didn't get hurt, but it is like a grenade going off.

Good luck,
Bill M
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Old 04-14-2008, 02:23 PM
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He's right about the Saginaw.Mine broke wothout even trying.That's how I ended up with the T-10
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Old 04-14-2008, 02:53 PM
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im in on the shatterproof i had a pressure plate explode in a 4x4 on me lucky me i still have my foot as it cut the gas pedal out from under my foot.
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Old 04-14-2008, 03:03 PM
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Old 04-15-2008, 08:41 AM
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Doesnt hurt to have a frt driveshaft loop too!!! David.
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