Dunno which heads you're speaking of: Gurney-Westlake built some three-valve hads (2 intakes & 1 exhaust) decades ago. They weren't popular since they were built for racing and high compression tended to collapse the too-thin combustion chambers. I think only a few sets were cast. They also built 2-valve heads with valves oriented straight across the chambers, just about the time SVO began marketing their alloy stagger-valve 'Boss-type' heads (1983). Again, only a few sets were built that I know of If you call Gurney Entrprises in So-Cal, you'll likely get Phil Remington on the phone and can get info straight from a principal player at Gurney's facility.
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