Muncie Speedo Gear Question

camarojoe · #1 07-25-2005, 08:28 PM

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** · #2 07-26-2005, 01:17 AM

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** · #3 07-26-2005, 10:59 AM

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** · #4 07-26-2005, 09:05 PM

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

Jacsey 70Z · #5 07-27-2005, 01:07 AM

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

**COPO** · #6 07-27-2005, 01:10 AM

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

**Hotrodpaul** · #7 07-27-2005, 02:32 AM

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

Paul

camarojoe · #8 07-27-2005, 05:08 AM

[ 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.

Keith Tedford · #9 07-27-2005, 03:58 PM

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".

Jeff Murphy · #10 07-27-2005, 07:05 PM

[ 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...

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?

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