rear end question ????

ok question is i just picked up a 3/4 ton crew cab for me a new cab ,aite im going to use the rear end out of it also to put under my dually ,cause its narrower,i anyone have any idea as to what gearing this thing may have ? its like and 81-83 ? had a 350 automatic in it . i looked in the glovebox but the sticker was wore off of course. im hoping its better than 4:11's which is whats under my dually now..is there anyway i can check the vin plate and see ?

Is there a tag on the rear end itself?

just pull the cover off and count them but its prolly gonna be 4.10s...time to change the fluid anyway haha

Or you can spin the tire once and count the # of times the pinion goes around to get a rough idea.

ok i dot the 3/4 rearend out spun the tire around twice and the yoke turned twice also so what would that be ?