Dana 60 gear ratio selection question

[usraptor]

How tall are the rear tires? Generally 3.23's are a lot nicer on the freeway than 3.54's are.

Runcharger, I'm running BF Goodrich TA radial 275/60 R15 on the rear.  They spec out at 28" diameter.

[usraptor]

 From Dr. Diff's website: https://www.doctordiff.com/dana-60-ring-and-pinion.html

DoctorDiff Drivetrain Components

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Dana 60 Ring and Pinion
$185.00
Gear Ratio:
3.23 DoctorDiff Gear (3 series carrier) (+$15.00)
3.54 Motive Gear (3 series carrier)
3.54 OEM Spicer (3 series carrier) (+$100.00)
3.73 Motive Gear (3 series carrier)
3.73 OEM Spicer (3 series carrier) (+$100.00)
4.10 Motive Gear (3 series carrier)
4.10 OEM Spicer (3 series carrier) (+$100.00)
4.10 Richmond Gear (THIN conversion fits 5 series carrier) (+$40.00)
4.30 Hoosier Gear (3 series carrier)
4.56 Motive Gear (THICK conversion fits 3 series carrier) (+$10.00)
4.56 Motive Gear (5 series carrier)
4.88 Motive Gear (5 series carrier)
Please, select one

[usraptor]

Okay between all your suggestions and communicating with Cass at Dr Diff I decided to go with the 3:23 gear set.  In the process of ordering gears, bearings, shims, gaskets, etc.  Anyway, he does not carry speedo gears.  Where can I buy a new speedo gears to match the new 3:23 gears? 
BTW, thanks for all the input?     As always, it's very much appreciated.

[Brads70]

Okay between all your suggestions and communicating with Cass at Dr Diff I decided to go with the 3:23 gear set.  In the process of ordering gears, bearings, shims, gaskets, etc.  Anyway, he does not carry speedo gears.  Where can I buy a new speedo gears to match the new 3:23 gears? 
BTW, thanks for all the input?     As always, it's very much appreciated.

First figure out what one you need, maybe someone on here will have what you need lying around?

[Cudamike]

http://www.mymopar.com/speedometer.htm

https://www.classicindustries.com/product/all-years/dodge/challenger/parts/mp14032.html?gclid=EAIaIQobChMIuZec4LSy4gIVmI3ICh0p_QrjEAQYAyABEgLu2fD_BwE

[usraptor]

Thanks Brad and Cuda Mike 

[Spikedog08]

Thanks Brad, hadn't thought about the speedo gear . . . If Roseville doesn't have them, I would check with Mancini Racing.  I too am ordering the 3.23!   Excited!   

[Brads70]

I have a green 34 tooth speedo gear if anyone needs?