Tire Sizes and how to calculate

[Layne Grissman <64Polara500@xxxxxxxxx>]

Does anyone know how to calculate final tire size when trying to keep
the RPM's down?  What is the typical RPM range I should try to keep it
in and at what speeds?  I was figuring about 2800 RPM at about 60-65
mph.....We have a 3.91 Sure Grip rear...Want to get the right tires
the first time....  :)  Is there a formula?

Also was the typical final gear on the A727 1.00??

Thanks all!

Layne
'64 Polara 500
'08 Charger
'08 Ram (yeah it's got a Hemi)