Muncie Speedo Gear Question

[Hotrodpaul]

What combination of speedometer gears would be correct for a 69 Camaro with a Muncie 4 speed, F70-14 tires, and 4.10 gear ratio. The Rick's catalog states that the driven gear should be green with 22 teeth but does not give a matching driver gear. What would be the correct color driver gear and number of teeth?

Thanks, Paul

[Mr70]

I thought it should be Part #3860348-Orange with 25 teeth?

[Hotrodpaul]

My tranny currently has an orange driven/white driver gear and came factory equipped with a 4.10 axle ratio. The original owner installed 4.88's and drag raced the car for several years but before I bought the car the original 4.10 gears were reinstalled. Maybe the speedo gear is OK.

The Rick's catalog must be incorrect then.

Paul

[Don_Lightfoot]

It wasn't mentioned, so you may have it. I believe the 4.10's with four speed also had an adopter (or whatever it was called) between the cable and tranny gear. My Camaro assembly manual is loaned out right now otherwise I could find the proper name.

[Kurt S]

[ QUOTE ]
I believe the 4.10's with four speed also had an adopter (or whatever it was called) between the cable and tranny gear.

[/ QUOTE ]
Some 4.10 cars have it, some don't. Depended on which trans part # they got.

[69L78]

My car has the M-21 with 4.10 posi and has the adaptor.

[Hotrodpaul]

My M21 transmission tag reads 3950316 which shows to be a M21 with L34 engine (396 350 Hp)from the Camaro Assembly Manual. They also list a 3946798 for M21 with Z28 and L78 so mabye this trans was pulled by mistake or they had a shortage of 3946798 transmissions. I think these kind of mistakes or substitutions were made quite often.

This M21 trans may also be the one used with 4.10 axle ratio's as well.

Paul
69 Camaro SS L78 M21 4.10's

[Kurt S]

Without digging back into it, I recall that one trans was for deep axle gears, one was for regular gears. The 4.10 was the crossover point and could use either, but needed the adaptor with the one trans.
I'd say you need the adaptor (or need to change the driver gear in the trans). You have the same trans # as Jeff (69L78).

[Hotrodpaul]

In the Camaro Assembly Manual, it shows the adapter being used with G80 positraction option but I don't think it mentions a gear ratio. I will check again.

Thanks, Paul

[camarojoe]

FYI, there are many different ratios on those adapters too, which throws yet another wrench into things... They were made by Stewart Warner, but factory installed ones also carried a GM part # too. The 4 speed Deuces used these. (4:10 rear ratio, M21 muncie)

The Yenko Deuce service parts catalog lists 2 numbers for the speedometer adapter. 6477965 and 6477964. I believe these are the GM part numbers, but SW also sold these with their own part numbers, with the ratio stamped on the end of them...I think the GM issued ones have the ratio stamped on the end as well...but offhand, i do not know what the correct adapter ratio should be. For as many cars as used these, its hard to find anyone who really knows much about them. I was told that they were required because there was not a plastic tranny gear that would work with a rear end ratio of 4:10 or numerically higher... but i just read above that some cars didn't use them depending on the trans, so if thats true, that disproves what i was told.

[YENKO DEUCE REGISTRY]

This topic was covered nicely in the Nova Times resto pics of Hasset's orange deuce. The part number and ratio are stamped into the end of it. Ed's COPO.com site has the necessary parts and part numbers for the adapter setup.

[Kurt S]

Marlin,
Do all Deuce's have the adapter?

It's probably less than 50% of 4.10 69 Camaros that have it.

[YENKO DEUCE REGISTRY]

Yes, all deuces have the adapter, including a/t cars.

[Jacsey 70Z]

Here's the one on my car, 70 Z28, M22 with 4:10 rear.
Jack

http://pic3.picturetrail.com/VOL17/1627096/5944722/105984111.jpg

[COPO]

I have the exact same one on my '70 Z w/M-22 and 4.10

[Hotrodpaul]

Where can I find the correct one for my M21 and 4.10s?

Paul

[camarojoe]

[ QUOTE ]
I have the exact same one on my '70 Z w/M-22 and 4.10

[/ QUOTE ]

They all look the same externally, but there are many different ratios, which are stamped on the end of the reducer. I know LVCamaro's 69 RS COPO has one, its an M22 with a 4:10. I'd like to know what plastiv speedometer gear is used when one of these reducers is NOT present with a 4:10 rear ratio. I didn't think they made one that would work and give an accurate speedometer reading.

[Don_Lightfoot]

Good point Joe. When I did up my Camaro in 1997, M20/4.10, the car did not have the adapter/reducer and I do not believe they were available at that time. I needed to try every different color of gear until I found one that was reasonably close.

[Hotrodpaul]

What color gears did you find that were close?

Paul

[Keith Tedford]

The adapter on our Chevelle has the white gear and is stamped 666F N8. I can only read the last two numbers on the next line "33".

[Don_Lightfoot]

[ QUOTE ]
What color gears did you find that were close?

Paul

[/ QUOTE ]
Sorry Paul, memory isn't that good. Also, at that time, it wasn't the most important thing in the world so it doesn't stick in your mind.

[MIKEYPARTS]

THE GM PARTS BOOK SHOWS
6261784 8T DRIVE NATURAL
3987920 20T DRIVEN BLUE
THE OTHER LISTING WITH AN ADADPTOR IS FOR A CHEVELLE
MIKE

[Jeff Murphy]

[ QUOTE ]
The adapter on our Chevelle has the white gear and is stamped 666F N8. I can only read the last two numbers on the next line "33".

[/ QUOTE ]

Probably .7333 or .8133. I have a couple of those here to try to match up to my COPO.

I've also managed to secure this cool bundle of parts to allow me to make up whatever ratio I end up needing...

http://imagehost.vendio.com/bin/imageserver.x/00000000/the2ts/driveparts.JPG

http://imagehost.vendio.com/bin/imageserver.x/00000000/the2ts/driveparts1.JPG

http://imagehost.vendio.com/bin/imageserver.x/00000000/the2ts/driveparts2.JPG

I've seen lots of the SW versions but never an AC version, which Ed C. is supposed to have come on the car. Anybody got a picture?

[SS427]

Wow Jeff, VERY impressive to say the least! Neat stuff! http://www.yenko.net/ubbthreads/images/graemlins/biggthumpup.gif

[MIKEYPARTS]

CHEVELLE ADAPTOR #3932220 STAMPED .7333-A
# 3890575 STAMPED .8319
#3925673 STAMPED 1.1111-V
MIKE

[Hotrodpaul]

Wow, I think my head is going to explode. I opened up a can of worms on this one!

I guess I will try what I have and see how far off it is, then make adjustments later.

69L78 - Do you have a number on your adapter since you have the same gears and trans # as mine?

Thanks,

Paul

[69L78]

The adaptor # is 6476736 with a 1:.777 ratio and I believe the gear is a blue one with 20 teeth.

[Mr70]

I saw those gears/parts were for sale on Ebay recently Jeff.
I thought of you right away,you adapter Monkey! http://www.yenko.net/ubbthreads/images/graemlins/grin.gif

[Jeff Murphy]

[ QUOTE ]
The adaptor # is 6476736 with a 1:.777 ratio and I believe the gear is a blue one with 20 teeth.

[/ QUOTE ]

Can you post a pic of the adapter? That sounds like the AC part number that Ed C. quotes...

[69L78]

Here is the info on my 69 L78 M-21, 4.10 posi. The tag on the sidecover is 3950316 and the adaptor is 6476736 with a ratio of 1:.777 and has a blue driven gear with 20 teeth. I also have a 69 RS Z/28 with an M-21 and 4.10 posi and no adaptor. The tag on the sidecover is 3946798 and has a driven white gear with 25 teeth. Attached are pics of the adaptor.

[69L78]

Another pic

[69L78]

Another pic, last one.

[Jeff Murphy]

http://www.yenko.net/ubbthreads/images/graemlins/beers.gif

[Jacsey 70Z]

Just for the record.. My original 70 Z28 M22 4:10 rear Ratio White gear (19 tooth) Gear box date M 9 (Dec 69) for my 04B Car. Also Stewart Warner # 666F AND 7333.
Jack

http://pic3.picturetrail.com/VOL17/1627096/5979015/106421960.jpg

[YENKO DEUCE REGISTRY]

[ QUOTE ]
Here is the info on my 69 L78 M-21, 4.10 posi. The tag on the sidecover is 3950316 and the adaptor is 6476736 with a ratio of 1:.777 and has a blue driven gear with 20 teeth. I also have a 69 RS Z/28 with an M-21 and 4.10 posi and no adaptor. The tag on the sidecover is 3946798 and has a driven white gear with 25 teeth. Attached are pics of the adaptor.

[/ QUOTE ]

This is the style used on the Deuces, not the square model as pictured earlier.

Anybody know much about the 'key' that is used to link the cable and the adapter? I bought the 'key', but the speedo still barely turns http://www.yenko.net/ubbthreads/images/graemlins/dunno.gif

[camarojoe]

[ QUOTE ]


This is the style used on the Deuces, not the square model as pictured earlier.



[/ QUOTE ]

You sure about that? I could swear that somewhere I have pics of Mark Hassett's orange car when it was being restored (Nova Times articles maybe?) and it had the square type... I was thinking this car was pretty original as far as parts go. http://www.yenko.net/ubbthreads/images/graemlins/dunno.gif

[YENKO DEUCE REGISTRY]

I believe Hasset's car had the original adapter as well, but thought it was the 'round' version. Somebody pull out the NNN resto article to make sure. Wayne took good pics of the stampings.

The key?

[camarojoe]

I dont have the article... I remember looking at it at bkh's and am going from memory, but I'm thinking it showed the square one... I also had some pictures of this car sent to me via e mail awhile back (years ago) and no longer can find them on my hard drive... that may be where i saw it if it wasn't shown within the Nova Times articles.

[YENKO DEUCE REGISTRY]

I'll check it out tonight when I get home, I have the articles.

[Nova Research Project]

Here are some scans http://www.yenko.net/attachments/151668-Dave_Belk%5C%27s_1970_Yenko_05_01_6fSM.jpg

[Nova Research Project]

Second one: http://www.yenko.net/attachments/151670-Dave_Belk%5C%27s_1970_Yenko_05_01_7aSM.jpg

[YENKO DEUCE REGISTRY]

Thanks Gregg, I pulled out my issues last night - May of 2001 http://www.yenko.net/ubbthreads/images/graemlins/biggthumpup.gif

What about the stinkin Key http://www.yenko.net/ubbthreads/images/graemlins/mad.gif

[Mr70]

Shot of S/W unit on my TH400.
http://img.photobucket.com/albums/v669/Rick_Peters/adapter0002.jpg

[Mr70]

Another View.

http://img.photobucket.com/albums/v669/Rick_Peters/adapter0001.jpg

[YENKO DEUCE REGISTRY]

Do you have a Key inside there?

[Supercar_Kid]

Found this link over at TeamCamaro. It may be helpful to some of you trying to piece setups together.
Set that Speedo! (v)

[Mr70]

Marlin..What Key?
I can remove it today & look,if you can elaborate.

SCKid
That Link doesn't work.

[YENKO DEUCE REGISTRY]

http://www.copo.com/speedo-reducer.htm

At the bottom are the parts for the speedo reducer, including the key. The parts book has the diagram as well, but something is wrong with mine - as in, it barely turns. If I put the cable directly into the tailshaft, the speedo goes nutz, but install the reducer and key and it barely turns http://www.yenko.net/ubbthreads/images/graemlins/dunno.gif

[Supercar_Kid]

Oops...try this (http://www.camaros.net/shop/speedo.html).