If you are finally going to upgrade your cylinder head for the only gas now available (unleaded) then one of the main changes you will need to make is to have hard valve seats installed for the exhaust valves. The single most universal exhaust valve size found in the 1275cc cylinder head is the 1.15". These hardened seats for 1.15" 1275 exhaust valves have an O.D. of 1.23".
Sold each. Four required per car.