Speedometer Gear Change Help!

[RrCoX22]

For an '82 CJ-5 with 300trans./case

Swapping from 2:72 gears w/31" tires to 4:10 gears w/33" and need to adjust the speedo and does the inner drive drive gear need to be changed? Have the dark green gear right now and need to know the process to line this up correctly.

[yellow85cj]

Speedo gear size app http://www.jeeptech.com/javaAps/Speedo.html

Size/color chart http://www.greatcj8.com/speedogear.htm

Gear teeth number is molded into bottom of the gear as there seem to be 2 green sizes on the chart.

Line the gear number that you have (marked on the gear housing) with the arrow on the shaft housing. It is cast into the housing but hard to see on an oily 300. It is marked in red in the pic.