im setting up the spring and shackle hangers for my SAS on an 88 4runner. im trying to figure exactly where to mount everything. how much caster do i want on the front axle. right now the upper and lower knuckle bearings are at 0. straight up and down.

 

7 degrees is perfect, but you can usually get away with 5.
One downside if its a toy housing, kinda shoves your pinion in the dirt...

 

7 degrees forwards, right? yeah its a toyota housing, i dont have the third member in yet, but it looks like im gonna have a pretty bad pinion angle

 

7 degrees positive caster(caster pointing upwards)

Ya, it pretty much screws the pinion angle unless you cut/turn the housing.