what $$ is a complete 8 3/4 worth?

Posted before.

$250 for the housing.
3.23 489 case sure grip already had -0-
Built a extra 4.30 489 case up $900 this is what it will cost to build any center, if you do not have one.
Dr. Diffs axles $330.
Brakes, about $150

So you are about $750 if you have a set of gears.
and about $1650 if you do not.

Next time I will spend my money on a Dana 60