8 3/4 vs Dana 60

Ace said
Not true. Ball (Green) bearings are fine for street use. Do a search to find the info debunking this myth. OBTW, tapered bearings rule out most aftermarket axles, so you're back to limiting HP to around 500 before the axles become the weak link.
You are right "green bearings" are fine for the street but they are not to be used for heavy side loading applications (like road racing or circle track) or for trucks carrying heavy loads. Call Moser, Strange, whom ever they will tell you the same thing.