I don't run a proportioning valve. All it does is reduce pressure to rear brakes. If anything I still don't have as much rear brakes as front. Makes no difference in 4wd though.

The other two lines were for the evap ****. I plugged them and now have no vent, would recommend having a vent. I think they ran a return to keep the fuel moving so as to prevent it from getting hot and vapor lock. Also convenient when converting to fuel injection.