I swapped in a set of 3.73 form a stock 3.23, how far + or - should my speedo be?

 

Try this, you have to figure tire size, too.

http://www.dakota-truck.net/TIRECALC/tirecalc.html

Google your question and see what comes up.

-Dave

 

Your speedo will read 15.5% higher than actual road speed. That would be a 70mph indication at a true 60mph. You are also adding miles to your car faster.... when you drive 1,000 miles, your odometer reading will increase by 1,155 miles.

To calculate it:

3.73 / 3,23 = 1.155