Back in the '70's I had the head off a 4 cyl L series engine, and it had bronze valve guides and bronze valves seats. Nothing special about the car, it wasn't an SS or anything, but always remains a puzzle.
In 1985, before the wave of domestic imports hit New Zealand, I did a head gasket on what I thought was a Datsun C240...but it was a 2 litre version of the 6 cyl L series engine. No parts were available in the country, so had to get a headgasket custom made. At the time I had just done engine rebuilds on a '64 220 and a '65 250 Mercedes, the similarities were obvious.