Axle shafts and 3/4 & 1ton

[wolfthing2000]

I am in the process of finding a 3rd member 4;56 ratio for a 69 K 20 rear axle.. That is the corporate axle dropout style( Eaton?). I have been told to look out for the spline count for the axle shafts as they differ for 3/4 and 1 tons.. The guy told me to check hex size on the axle flange bolts:::::::::: 3/4 inch ( what I have on the K-20 which to my knowledge came with the truck from factory) indicates a 1 ton. In other words it takes a 3/4 socket or wrench to remove the bolts. But he says the 3/4 ton axle has 5/8 bolts and a different spline count????

What is there to this?? Any fact here or just backyard talk??

I will pull an axle before I head to the salvage yard to be sure.
Thanks,

Dave