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.