Soothe my ignorance

[n3w6uy]

I know nothing on this topic. How would I go about finding my Valiants gear ratios? Ive got a 70 with a 318 and a 72 with a 225. As far as I know both drive trains are stock. Are there casting numbers or is it a take-it-apart-and-look kinda deal?

 

[MtNemoMopar]

They all had tags on the rear pots with the ratio stamped on. If these are gone, just turn your driveshaft, and count how many turns it takes to turn the wheels one full revolution. Example- 3.5 turns of the driveshaft would likely mean 3.55 gears.