If you pull the old chunk out, you can divide the gear teeth to get the ratio. Simply count the number of teeth on the ring gear (big one) and divide by the number of teeth on the pinion (small gear). Worked perfectly for me on the 2.80 I had in my rear, even though I had trouble with the "spin the wheel" method.
As for the switch, I see no reason not to upgrade to the 9" other than to avoid the hassle. Considering that it's not a huge amount of time or money to pull your axles and replace the bearings, that may be your easiest solution.
As you likely know, the primary reasons for upgrading to a 9" is when your engine make 300+ hp (popular opinion?). The reason to change gears is to make them match your wants for using your car's power (top speed or off the line gearing).
I did not know anything about this before the VMF - I'm sure others with more first hand experience can be more specific / helpful than I - Dickson
1965 GT fastback / "Fastbasketcase" (by Midlife)
There's a fine line between "hobby" and "mental illness" - Dave Barry
As for the switch, I see no reason not to upgrade to the 9" other than to avoid the hassle. Considering that it's not a huge amount of time or money to pull your axles and replace the bearings, that may be your easiest solution.
As you likely know, the primary reasons for upgrading to a 9" is when your engine make 300+ hp (popular opinion?). The reason to change gears is to make them match your wants for using your car's power (top speed or off the line gearing).
I did not know anything about this before the VMF - I'm sure others with more first hand experience can be more specific / helpful than I - Dickson
1965 GT fastback / "Fastbasketcase" (by Midlife)
There's a fine line between "hobby" and "mental illness" - Dave Barry