8 3/4 woes

sounds like you chucked some teeth -- why build another 8-3/4 -- sounds like you actually drive your car the way it was meant to be driven -
go with the 9 inch Ford --strong differential ,, gear selection is extensive , parts readily available -- call Moser or Strange Engineering with the housing measurements you need to fit your car --you can have 8-3/4 flanges installed on the 9 inch housing to reuse your stock brakes - go with 35 spline axles ( Detroit lockers are available for this axle spline if you spend more time on the street ) -- 1350 u-joint yoke -- with a similar size driveshaft ,,,, yes it will cost $$$$ but do it right and you will never look back.

as far as horsepower loss it's nothing you will notice .