4 speed speedo drive colors?

[cjw916]

I'm sure I've seen this before, but I rebuilt my 4 speed this week (Brewer's kit, new synchros, main bearings, needle rollers, gaskets, circlips, O-rings, yoke bushing & seal) & re-installed it with a new McLeod 11.95" organic/ceramic diaphragm clutch (had flywheel ground).

Everything went fine. My pro wrench friend asked me to pick up a pinion seal, and I said I was thinking of swapping my 4.10 gears to 3.55 so my speedo would be accurate. I think a 3.55 would be plenty quick, when I was 15 I wanted a street-light racer, and the car is very very quick, but now that I'm 40, 3700 revs to do 70mph is a little ridiculous. I have a green speedo drive gear, and if I do the Math between GPS & my speedo, it says 3.55 gears would put my speedo 'dead on'.

I think I'd be happy if the car was doing, what the speedo said, at any given revs.

What are the other color speedo drives & what gears do they correlate to?

Any advice on my 3.55 thoughts? 440, dual quads, Eddy heads, 4 speed, 8 3/4" rearend.

Thanks,

Christopher

[RallyeMike]

Information missing here is your rear tire height.

Google "727 speedometer gear chart" and you will get charts that match tire diameter to # gear teeth, and a chart equating color of gear to # of teeth.

[John_Kunkel]

Here's a list of the gears, their color and current P/N but, as stated, you need the tire diameter to determine the correct gear.

24 WHITE   3410024
25 BLUE     3410025
26 RED      2538926
27 WHITE  52068149
28 BLUE     52068150
29 BLACK   52068151
30 YELLOW 52068152
31 GREEN   52068153
32 BLACK    52068154
33 YELLOW  52068155
34 GREEN   52068156
35 ORANGE 52068157
36 RED       52068158
37 WHITE    52068159
38 BLUE      52068060
39 GREEN   52068061
40 ORANGE 52068062
41 RED       2538941
42 WHITE   2538942
43 BLUE     2538943
44 BLACK   2538944
45 Yellow   2538945

[cjw916]

Sweet!

That's exactly what I was looking for!

Thank you!

[fy469rtse]

And when you reference the chart, find the size that matches and the go one down ,
Maybe John can answer why it is that it ends up closer to correct speedo reading

[John_Kunkel]

I never use the speedo to check for drive pinion correctness, instead I use the odometer because it's driven directly whereas the speedo involves a rotating magnet.

If the speedo reads wrong with the correctly calculated pinion and the odometer is correct, the speedo is worn out.

[cjw916]

And, oh no. . .  :-)