by Eric Gibeaut in the January 1996 RootesReview
According to Rex Funk-who has authored several Alpine articles in the TEAE newsletter, as long as the engine is apart, go ahead and update the cylinder head to use unleaded fuel. Valves may be used from a Datsun 510 while lead-free seats are pretty much an off the shelf item.
Based upon my own experience, since leaded fuel became unavailable, I have continued to drive my 1967 Alpine just as I have in the past I’ve never added a lead substitute to the gas or done any engine work to update the engine. Two years ago I had to remove the cylinder head to replace the head gasket. While I had the head off, I could see no signs of valve or valve seat problems. If your valve clearances continually need adjusting that is a sign of trouble brewing.
I would welcome others input about this problem. Has anyone had problems resulting from the use of lead-free fuel in a Sunbeam?