M 21 transmission, any way to tell what it's from?

[trim code 188]

I have a Muncie M-21 ? transmission I want to use in this 350 car. It has a 10 spline input shaft, the speedometer cable hook-up is on the passenger side, the gearbox casting number is 3925660, with 13, and 2 above the drainplug. The tailshaft housing is casting 3857584, the only thing that looks like it might be a serial number? is on the right rear side of the gearbox. It is, 29P361437 also, P9B27A

Is there any way to know what year/model this trans came from?

I went to buy a clutch & pressure plate today and i'm not quite sure what to buy. Is the ten spline correct for 1970? The parts book lists 10&1/4" clutch plates, and also 11" plates for 70 GS 350. I did buy a pilot shaft bearing. I had a choice between bushing, and bearing, so I opted for the needle bearing.

[Scott Miller]

http://www.4speeds.com/muncie2.htm

http://www.4speeds.com/casting.html

clutch 10 1/2" for 350 & 11" for 455

I use the bushing, I have had problem with the needle bearings.

[kennygs72]

the gearbox casting number is 3925660 this is a 68 to 70 main case

The tailshaft housing is casting 3857584, this a 65 to 70 tail hoseing with the pass side speedo.

P9B27A this the productio code and breaks down into the following;
p= pass car
9=1969
b= 2nd month ( feb)
27- 27th day of feb
a=2:52 first gear wide ratio m20
hope this helps, kenny

I have a Muncie M-21 ? transmission I want to use in this 350 car. It has a 10 spline input shaft, the speedometer cable hook-up is on the passenger side, the gearbox casting number is 3925660, with 13, and 2 above the drainplug. The tailshaft housing is casting 3857584, the only thing that looks like it might be a serial number? is on the right rear side of the gearbox. It is, 29P361437 also, P9B27A

Is there any way to know what year/model this trans came from?

I went to buy a clutch & pressure plate today and i'm not quite sure what to buy. Is the ten spline correct for 1970? The parts book lists 10&1/4" clutch plates, and also 11" plates for 70 GS 350. I did buy a pilot shaft bearing. I had a choice between bushing, and bearing, so I opted for the needle bearing.

[Marco]

Ill add this for the 29P361437 serial number...

2 - Pontiac
9 - 1969 model year
P - Final assembly plant - Pontiac MI
361437 - serial number of original car.

[trim code 188]

That site, and those posts were all extremely helpful. Thanks a bunch to all. It looks like i can use this trans. Soon, another four speed GS in the world.

[trim code 188]

What is the proper finish for the main case? This one looks to be painted with silver/ aluminum paint. Is that correct? The rear housing is natural aluminum. How can I make this trans look correct? On a budget? Thanks