Speedo gear reduction

[L78 steve]

Would a 67 Camaro, 4.10 geared use the external speedo cable reducer?
My 69Z has the red plastic gear for 4.10 but no external reduction.

[L78 steve]

Anyone?

[Kelley W King]

I have never seen a car come with that device. Why? they have gears for all factory ratios. I think that device would be for non factory gears like 586 or 614?

[firstgenaddict]

It depended on the trans and rear ratio along with tire size whether or not it got the reducer. The M20 4.10 69 Z with low miles I restored did not have a reducer. 

[JohnKY]

If the car originally had 14" tires, it would use an adapter, with 4:10 gears.

[L78 steve]

If the car originally had 14" tires, it would use an adapter, with 4:10 gears.

This is what I thought. My 67 has 14" tires with 4.10 and none of the avail. trans. gears are correct. the 70 LS6 4.10 used this adaptor.

[x66 714]

1968 Z/28 with 4:56 gears had one from the factory. Not like those pictured...Joe

[L78 steve]

1968 Z/28 with 4:56 gears had one from the factory. Not like those pictured...Joe

Was it a Stewart Warner 666 ? should look similar to above pic.

[JohnKY]

Both the 67 (4spd., 14" tire. 4:10) and the 68 Z28 (4spd., 15" tire, 4:56) would have used the same adapter. Part #6476735 with a gear ratio of .8235.

[L78 steve]

Thank you for the info.

[luv2sixty9]

Both the 67 (4spd., 14" tire. 4:10) and the 68 Z28 (4spd., 15" tire, 4:56) would have used the same adapter. Part #6476735 with a gear ratio of .8235.

I have a 67 Z28 with factory 488 gears and it has an adapter. If my memory serves me correctly I believe its also 6476735 and my car has the 15x6 / 15" tires

[L78 steve]

I installed the adaptor in the 67. There is barley room for the cable due to the 396 being shoved over another 3/4" . Hope the sharp radius in the cable is OK. I will take a pic. Anyone else with this set-up?

[KurtS]

This has been discussed before.
As I recall, there were different Muncies with two different driven gears. The one version was for the steeper rear gears and could be used with non-steep gears with the adaptor.

[L78 steve]

It depended on the trans and rear ratio along with tire size whether or not it got the reducer. The M20 4.10 69 Z with low miles I restored did not have a reducer. 

My 69Z 4:10 Rear also no reducer. It uses the 25 tooth natural color gear.

[Rufcar]

I know I am late to the party but what I did was get 3 or 4 different color (teeth count) speedo gears then I used my GPS to get my actual MPH and Id change until I got to the correct speed on the GPS and if the speedometer is off a bit after that, just make a note of how far off one way or the other for you record.
I started by counting the teeth and then ordering the gear I thought Id need and this took way too long as the gears are not that expensive. It def saved me a ton of time. I got some gears off ebay the others at a GN dealer.