§ Ms Glenda Jackson
Engine adaptations should not be necessary for the majority of motorists who switch from leaded to unleaded petrol containing lead substitutes. This "lead replacement petrol" will be marketed with an equivalent octane level to that of leaded petrol and will contain a lead substitute that will provide satisfactory protection against engine wear under mixed motoring conditions. Increased wear of exhaust valve seats may arise in vehicles driven predominantly with high engine speeds or high loads. Should this condition occur, engine modifications would then become necessary.