To install front discs on a 3800 why couldn't you simply remove the drums from the hubs and mount REAR disc rotors (with lug holes instead of studs) onto the hubs, then fabricate a bracket to mount the calipers? That way no need to find an integral rotor/hub that will fit the spindle.
Yes, I know Hollister makes a front disc brake kit but I don't want to use it because it spaces the wheels outward another inch on each side.
