CREATE TABLE table_75416 ("Model" TEXT, "Engine" TEXT, "Displacement" TEXT, "Valvetrain" TEXT, "Fuel system" TEXT, "Max. power at rpm" TEXT, "Max. torque at rpm" TEXT)

What Valvetrain has a fuel system made up of petrol engines?
SELECT "Valvetrain" FROM table_75416 WHERE "Fuel system" = 'petrol engines'
SELECT "Valvetrain" FROM "table_75416" WHERE "Fuel system" = 'petrol engines'