4:10 Dana - F60x15 Polyglas Speedo Gear Size

[TWS]

1970 E-Body Dana 4:10, F60 Polyglas.  Charts say it should be a 41 speedo, buildsheet says 42.  Charts say for this config a 42 would be a 4:30 gear.

Any 4:10 Dana / F60 Polyglas cars with their buildsheet?  If so, what does it say for your speedo gear number?  Thanks!

[VCODE]

1970 E-Body Dana 4:10, F60 Polyglas.  Charts say it should be a 41 speedo, buildsheet says 42.  Charts say for this config a 42 would be a 4:30 gear.

Any 4:10 Dana / F60 Polyglas cars with their buildsheet?  If so, what does it say for your speedo gear number?  Thanks!

Tim,
My Challenger with 4:10 has 14 inch wheels & tires. Broadcast has a 41 tooth.
I would say the 42 sounds correct with 15 inch.
They are off a little. Not perfect.
Bob

[6bblgt]

42 

[6bblgt]

1971 used 42 also 

[mrwfp]

Tooth count has always been confusing to me.  With a Dana 60, 4.10 gears and 50 series radial tires on the rear, I was using a 42 tooth speedo gear. The speed was always showing about 7% faster that my actual speed but the odometer was exactly correct. I am more concerned about having correct mileage than correct speed. When I changed the rear tires to 60 series radials of course both speed and mileage were off using the 42 tooth gear. I changed to a 38 tooth gear and both the mileage and speed were still off. I then installed a 39 tooth gear and I am back to the mileage being spot on but the speed shows about 7% fast again.  I have never understood why I can never get both speed and mileage to be correct at the same time.  Is it the speedo? It was supposedly calibrated before it was installed.

[anlauto]

The chart I have saved says 42 

[TWS]

Thanks guys for the buildsheet info!  As far as gear charts, I did not come across the version you had alan, multiple sources with the data I mentioned above which prompted my original question.