Vette5311

Something else I forgot to ask, if anyone knows off the top of your head. I will be looking for a new slip yoke for a muncie. Are all ujoint cups for these the same size or did they make different ones for the big block / small block.
Thanks again.

DZAUTO

The U-joint cups are all the same size for transmissions that have the 27spline tail shafts (or 16splines for T-10s).
Where a difference may occur is with the 71-74 Muncies and later Super T-10s which had the larger 32spline tail shaft.

DZAUTO

Well, I've been screwing with, busting knuckles, cussing and fighting old Chevys (started with a babbit beater) and Corvettes for over 55yrs (as well as a few HEMIs, Pontiacs, Olds and Fords). In fact, I do own ONE Ford--------------------------but it's built tough with Chevy stuff!

tbarb

You are definitely doing right changing the transmission to a Muncie or a later much stronger ST-10. If it has not all ready the big block will twist the course spline tail shaft or the input shaft. The small iron front bearing retainer dates back into the forties, I can only assume GM installed the aluminum front bearing retainer to go with the 1963 aluminum bell housing for 1963.

I would sell it as is, chances are the gears all need to be replaced along with the sliders etc for a proper rebuild.

Post the #'s stamped in the main case just below the WC2832 assembly date and a better picture of the tag attached to the side cover bolt.

The 621 bellhousing you report is probably the original to the car.

Vette5311

The Muncie I'm looking at I believe is a 67 but not sure. It has the speedo cable out of the driver side no the passenger side so I believe that makes it a pre 1969 one. It has bolts that hold the shifter arms on the side cover not studs so again I think it is a later one. I will have to do a spline count on the out put and look for a P code for date.
Thanks again.

Vette5311

I am definitely going with the Muncie, just makes more sense. Thanks

DZAUTO

Whichever side the speedo fitting DOES NOT necessarily determine the year model of the transmission.
Muncies in Chevrolet products were on the LEFT side up through 65, then in 65 they put the speedo fitting on the right side. BUUUUUUUUUUT, some cars, such as Pont GTOs continued to have the speedo fitting on the left side up to about 1970.

Muncies had the shifter levers attached by studs/nuts through 68. In 69-later, the shifter levers were attached with bolts.
Now, with that said, studs/bolts for attaching the shift levers is NOT a guarantee of 68-earlier or 69-later unless it is an unmolested virgin tranny. Over the years I (and other people) have pieced together Muncies from various parts, including using early or later shifter shafts on early or later Muncies.

GTOguy

No matter what 4 speed you end up with, they all will give you a 1:1 4th gear. So if your 4.11 is too high winding for you, you may want to swap the rear center section for something more user-friendly. Keep the close ratio for 3.70--4.11, but if you go 3.08-3.36-3.55, a wide ratio Muncie will suit your needs better due to the lower 1st gear ratio that it has.

Vette5311

Thanks, I think I will keep the 4.11s because eventually I plan on a 5 speed with O/D

Vette5311

I will get the P code tomorrow, that should tell us the date of the trans regardless of parts swapping. Thanks

Vette5311

I got the Muncie today. P code P0627 I'm thinking June 2, 1967 27 spline output close ratio. Supposedly out of a 1967 Firebird HO with 400. I does have the single ring on the input which I believe the factory used to mark close ratio. No metal in the oil, and with side cover off all gears and rings points are pretty sharp and pointed, not rounded and worn down. I sent the shifter to Hurst for a rebuild.

Vette5311

The Muncie has a green plastic driven speedo gear, I believe this is correct for the 4:11 Does anyone know for sure? Hate to try and change it once it's in the car.
Thanks

plaidside

I believe SWCDuke posted this.
Joe

Axle-------drive/driven

3.08-------8/18
3.36-------8/20
3.55-------8/21
3.70-------8/22
4.11-------8/24
4.56-------6/20
Duke

PS
ratio__ tire size __drive gr____ driven gr_ teeth__color
2.73__8.15-G70__3895494____3987918_18____brown
3.31__8.45-G70__3924098____3987919_19____natural
3.36__8.15-G70__3924098____3987920_20____blue
3.55__8.15-G70__3924098____3860344_21____red
3.70__8.15-G70__3924097____3860345_22____green
3.70__8.45-____ 3924098____3860344_21____red
3.73__8.15-G70__3924097____3860345_22____green
3.73__F70______ 3924097____3860348_25____orange
4.10__8.15-G70__3924097____3860347_24____yellow
4.11__F70______ 3924097____3860348_25____orange
4.56__8.15-G70__3924097____3860345_22____green*** uses 3890575 adapt

DrainSurgeon77

P0627 is June 27th 1966 if it has a 5010 main case...

Hope this helps... Eric

Vette5311

I was not sure I was reading it right. Thanks

Vette5311

I am a bit confused here. I have read else where green was for the 4:11. (Heartbeat City) I don't know what the number of teeth on the drive gear on the mainshaft are, and I don't really want to remove the tail shaft housing to find out. I realize the tire size will affect this reading but that will be close enough for me. However, getting the wrong color gear will be quite a bit off. According to your post I should have the orange gear if I read it correctly. Thanks

Critter1

In my 1966 printing of the GM parts book, a yellow 24 tooth speedo driven gear is shown for a 4,11 rear end ratio.

Vette5311

I will check to see that it is a 24 tooth driven gear and get a yellow one then.
Thanks

GTOguy

Takes but a minute to pull the driven gear and shine a light into the hole and count the drive gear teeth. Especially sitting on the bench. Probably less than a minute.......

JohnZ

Here's everything you need to know about Corvette speedo drive and driven gears.