Silicone heater hose, 42" for cars with the original heater valve bolted on the cylinder head.
Cars after 1976 require one of this 42" length and one
C-GRH1006 39" length.
Cars from late 1984 to 1988 had 5/8" outlets on the heater matrix so these hoses will need to be lubricated and pushed on extra hard to fit-originally on these year cars Rover fitted a flared 1/2" hose that was discontinued.