Question: What driven gear for speedometer?

[jackfit]

There are about 6 or 7 gears of different number of teeth 18 to 25. Other than getting the same color that comes out of your transmission. How do you choose. I have a 4 speed M-20 wide ratio Munice in with a 308 rear, which one for 336. I have a 66 vette L79. Which one do I order . Thanks

 

[67HEAVEN]

jackfit,

This link should help.

Set That Speedo!

Once you've determined how many teeth you require, you can order from the suppliers based on that information.

 

[WayneC]

There are about 6 or 7 gears of different number of teeth 18 to 25. Other than getting the same color that comes out of your transmission. How do you choose. I have a 4 speed M-20 wide ratio Munice in with a 308 rear, which one for 336. I have a 66 vette L79. Which one do I order . Thanks

3.36 takes the blue 20-tooth driven gear, I believe, #3987920
Your current 3.08 should have a brown driven gear #3987918 (18 teeth)

 

[jackfit]

67 Heaven,

Thanks, I looked at the site and it was helpful. I did come up with 18 tooth for the 3.08
using the RPM chart.
Which gear in your speedo do you count?

Jack

 

[jackfit]

Thank you WayneC,

I will buy both and check it against the RMP. My speedometer hasn't worked since I bought the car in 1970. This time I am doing the resto myself (see my album) except for the engine and paint. When the car wasn't a legend back in 1972, the orginal cable broke off inside of the speedo head, and the Chevy dealer didn't want to fix it, I put a Sun speedo inside the cluster, it was too small so I painted black paint around the glass to block off the inside of the cluster, ahh the things you do when you are in your early 20's. I wish I was in Santa Barbara right now. It is 5 outside with snow on the coast of Maine where I live.

Jack

 

[WayneC]

When the car wasn't a legend back in 1972, the orginal cable broke off inside of the speedo head, and the Chevy dealer didn't want to fix it, I put a Sun speedo inside the cluster, it was too small so I painted black paint around the glass to block off the inside of the cluster, ahh the things you do when you are in your early 20's. I wish I was in Santa Barbara right now. It is 5 outside with snow on the coast of Maine where I live.

Jack

Reminds me of a story.
Way back when, I took my year-old 63 Vette to a Chevy dealer for a new clutch. I stopped back to pick up the car, but it wasn't yet completed and I walked out in the shop to look at it on the lift (back then you could do things like that)... the "mechanic" had allowed the rear of the engine, now free of the bellhousing & tranny and thus free of the rear engine support, to actually hang by the tachometer cable (with no jackstand under the rear of the engine). I raised holy hell and was assured that the distributor & tach would be fixed if they were broken. Later when I picked up the car the tach worked, so I assumed they fixed it, but it lasted only a few weeks.... of course, when I took the car back the dealer said it wasn't his fault, it had been working fine when it left his shop! Frankly, I didn't want to entrust the car to him again, anyway, and I never went back there. I repaired it myself.

It's sunny in the mid-60's today.