Muncie Speedo Gear Question
 

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

Re: Muncie Speedo Gear Question
 

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

Re: Muncie Speedo Gear Question
 

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

Re: Muncie Speedo Gear Question
 

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.

Re: Muncie Speedo Gear Question
 

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

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

Re: Muncie Speedo Gear Question
 

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

Re: Muncie Speedo Gear Question
 

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

Re: Muncie Speedo Gear Question
 

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).

Re: Muncie Speedo Gear Question
 

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

Re: Muncie Speedo Gear Question
 

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.

Re: Muncie Speedo Gear Question
 

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.

Re: Muncie Speedo Gear Question
 

Marlin,
Do all Deuce's have the adapter?

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

Re: Muncie Speedo Gear Question
 

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

Re: Muncie Speedo Gear Question
 

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

http://pic3.picturetrail.com/VOL17/1.../105984111.jpg

Re: Muncie Speedo Gear Question
 

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

Re: Muncie Speedo Gear Question
 

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

Paul

Re: Muncie Speedo Gear Question
 

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

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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.

Re: Muncie Speedo Gear Question
 

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.

Re: Muncie Speedo Gear Question
 

What color gears did you find that were close?

Paul

Re: Muncie Speedo Gear Question
 

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".

Re: Muncie Speedo Gear Question
 

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

Paul

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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.

Re: Muncie Speedo Gear Question
 

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

Re: Muncie Speedo Gear Question
 

[ 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".

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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/imag...driveparts.JPG

http://imagehost.vendio.com/bin/imag...riveparts1.JPG

http://imagehost.vendio.com/bin/imag...riveparts2.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?

Re: Muncie Speedo Gear Question
 

Wow Jeff, VERY impressive to say the least! Neat stuff! https://www.yenko.net/ubbthreads/imag...iggthumpup.gif

Re: Muncie Speedo Gear Question
 

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

Re: Muncie Speedo Gear Question
 

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

Re: Muncie Speedo Gear Question
 

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

Re: Muncie Speedo Gear Question
 

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

Re: Muncie Speedo Gear Question
 

[ 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...

Re: Muncie Speedo Gear Question
 

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.

Re: Muncie Speedo Gear Question
 

Another pic

Re: Muncie Speedo Gear Question
 

Another pic, last one.

Re: Muncie Speedo Gear Question
 

https://www.yenko.net/ubbthreads/imag...lins/beers.gif

Re: Muncie Speedo Gear Question
 

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/VOL17/1.../106421960.jpg

Re: Muncie Speedo Gear Question
 

[ 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 https://www.yenko.net/ubbthreads/imag...lins/dunno.gif

Re: Muncie Speedo Gear Question
 

[ 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. https://www.yenko.net/ubbthreads/imag...lins/dunno.gif

Re: Muncie Speedo Gear Question
 

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?

Re: Muncie Speedo Gear Question
 

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.

Re: Muncie Speedo Gear Question
 

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

Re: Muncie Speedo Gear Question
 

Here are some scans https://www.yenko.net/attachments/151...05_01_6fSM.jpg