73 Duster speedometer reads wrong

dodge freak said
u sure it has 3.23 gears

Yes..changed from 8 1/4 to a 8 3/4 with 3.23 gears...

I believe the orginal gear was a 33 tooth for the 3.21 gears...

anyway..i will just disconnect it...been driving it for years now without a speedo..

well...got another idea....using a rpm/tire dia/gear ratio calculator...it says at 2000 rpm I should be going 45 mph...
going to check it in the morning and see how far off I am...and then see if I can adjust it using a different speedo gear with more teeth..