Flo's does a great job of producing hard to find parts for the AE86! 

This 20v RWD Coolant Line Swap Kit includes a slim Rear Coolant Bypass Housing with Heater option and Top of Engine Coolant Outlet! 

Can be used on Silvertop Or Blacktop engines. 

The Kit requires use of the original RWD Water Pump(from an ae86), Water Pump Pulley, Alternator Bracket, Crank Pulley, Dipstick and guide, Thermostat Housing and Radiator Hoses.