what is the standard ratio for a lwb k10 with a 4 speed and a 283?

are any type of optional ratio's available for both a front and a rear axle?...hiway gears?

are any current posi, or limited slip differential available?

what can I expect to pay to have one rebuilt with new gears, bearings posi and everything else? a price check on front and rear axles?

the rear end is a corporate rear, the front is a closed knuckle front axle with drums and needs just about every thing.