That is a 64-65 trans but I can't see the input shaft. Does anybody know if you can run a 10 spline input shaft with no rings that identifies it as a M-20 and use a M-21 2.20 first gear or gear cluster. I have a trans that has that 10 spline input but the owner claims it to be a M-21. What is the spline count on a M-21 first gear compared to M-20?

I understand that a stock untouched trans would be strait forward, but this has a 64-65 front case and a newer tail end case. ( the speedo is on the passenger side which is not 64-65.)Could somebody mis-match a 63-65 M-20 10 spline input shaft with M-21 gears? Eg, the 1st gear ratio.

I have to turn the 10 spline input 2.5 turns to make the tail shaft turn one full rotation, so that's a M-20 I guess? This trans has the wrong tail housing so what would it take to change it to a 64-65 one with the proper speedo ratio and drivers side attachment? This trans has the speedo on the passenger side. Is there a way to check if this set up will work with my speedo? I have a 3925661 trans that is a 1970 I think, the speed was always off by 10 MPH, and it had the speedo attachment on the passenger side. Could this trans be a newer M-20 with a 64-65 front case? How would you know? The 10 spline input has no groves.

Have you checked this site out ? Some good info on the Munci trany's and some mention of the T10 and super T10.  Looks like you can tell wide and close ratio on the super T10 by groves on the input shaft but your right how do you tell on the
T10 as both have no grove.  Maybe RacerRick can help ?



http://www.angelfire.com/fl4/pontiacdude428/tranny.html

Hey good news Rick, turns out that I think the second trans I purchased is a M-20, not a M-21. The one in the Blue 65 SD 4spd is also a M-20. Man these trans have a lot of different styles.

I have one sag but I have heard that they are weaker. Someone I know made the statement that there is a big sag that is strong, but I have never seen one. He's running it in a 400 HP car and it hasn't blown yet.

Ya those ST10s are a great tranny. A 77-79 Z28 model has the 3.08 1st gear and the 80-81 Z28s had the 3.42 if I remember right. The 3.42s have a huge jump to
2nd gear though

Muncie Find! I found a date correct M20 for my 67. It was new never used. The tranny was in a tech school on a stand for a viewing example. Had to pay big bucks but thought it was worth it as most of these used ones need new clusters, bearings anyways.

here's a '63 tailhousing on ebay...
i bought some gears from him, no problems, accurate shipping.

http://cgi.ebay.com/ebaymotors/MUNCIE-4-SPEED-1963-TAILSHAFT-HOUSING-CAST-3831731_W0QQitemZ200330044747QQcmdZViewItemQQptZMotors_Car_Truck_Parts_Accessories?hash=item200330044747&_trksid=p3911.c0.m14&_trkparms=72%3A1205%7C66%3A2%7C65%3A12%7C39%3A1%7C240%3A1318

65sssd wrote:

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Lemans64 wrote:

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gee maybe I should trade u my 21 for your 20, LOL. Mind u, u would still need a tail housing, LOL.

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Ahh!! The shoes on the other foot now! The M-20 was what I was looking for but the guy I bought the two trans off told me it was a M-21. I ended up with two M-20's. Ones in my Blue SD right now, what a bonus. There is a 66 M-20 in Vic for 800.00 right now. Little steap for a used trans.

 

 

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Spending all money on paint, so there won't be any tranny mods this year. I'm getting used to the 21 anyway, that first gear stretches out a long way. My buddy with a 65 cuda is in 3rd while i'm still in first, LOL.  I't got a good clutch so we should be ok.  Called your cell today and left message. around 3pm.

Ya we are off to my parents place in Cassidy tomorrow. Hopefully things come together soon on the paint thing, otherwise I might miss the summer fun. My bodyman has kinda got all messed up so might have to find someone else. Hopefully soon. Just don't wonna pay 100 bucks an hour for it, Getting cheap in my olds age, LOL. Can't ait to see the blue car. Looks nice in the pictures.

I do have a possible line on a couple of guys I used to work with, possibly around 40 an hour. Ya I hear ya on the 10G paint job, I just can't go there. U do body work ?? HHMMMM, LOL. Painter works for a bodyshop right now and would be doing the paint work after hours or when slow so not to interfere with work. Would use their booth as the paint is waterborn and booth must be used.