'80 720 Axle ID

[Stinky]

I am trying to change axle ratios on my 720. I have the 3.73? ratio. I am in touch w/a guy 5 states away. He has a '80 720. The plate inside the passenger fender. It is dif style and it doesn't have the axle code on it.

 

Any other easy way to find it out?  I mean by finding a code...I know how to turn the axle and count turns.

What should it be?

Is there another plate?

I have gone to 15" tires and my truck is sorta boggy...it needs some rpm.

I already have rolled D21 and it should have a 4.11 in it. But, it is a bit wider, and the E-brake hook up is dif. I'd have to adapt that and also change the perches. I'd rather drive out to Riverside, CA and snag it and come back.

 

Will a 620 dif fit?  I've read that a 620 axle will fit...dat tru?

[datzenmike]

You have already started this same topic. 

Now you have two and will end up with multiple answers that others aren't aware off were tried. Keep track of your posts and add to them.