68-72 HO52 Question

[Mapleleaf]

Sorry if this is in the wrong spot I’ll move it if it is. I’ve been told that a 68-72 4:10 pumpkin from a Eaton H052 or 72 will bolt into my 49 3600. I‘ve got 4:57’s now (and I actually have a spare one as well).

How hard is it to get a 4:10 H052 from a 67-72? How common were they? Did they come in particular models in that year or particular engine/tranny combos?

Are there any codes on the outside of the axle that give the ratio?

Any help appreciated – I’d like to do a swap in the spring if I can find the parts.

Again, if this is in the wrong forum I’ll move it.