"Peter Dohm" wrote

That is an interesting assertion. I really don't know. The number would
conform quite nicely to a 1600cc/96cid engine producing around 60hp; as
well
as most older normally aspirated aircraft engines, which seem to have
maximum continuous power figures in the 0.5 hp/cid range. There is even a
rather famous dissertation, supposedly published in Contact!, which
suggests
failure due to heat dissipation problems in the valves and/or heads of
automotive engines operated above continuously that power level.

You have no doubt read ditties from VeeDubber here, and one of them was on
VW engines, and how many HP they really can sustain.

Seem as though (from nearest I can remember) the amount of cooling fins in
the area of the valve guides and seats, and the cross area is insufficient
to carry away the amount of heat that is flowing through that area, if it is
run flat out with a big enough prop for very long.

Remember, heads in most auto engines nowadays, are cooled by water
circulating through the head. Flow some oil past the critical areas, and
heat can be dealt with. Air cooled engines must depend on cooling fins, and
enough metal to carry the amount of heat produced to the fins.

Perhaps VeeDubber will be kind enough to repost that treatise? g
--
Jim in NC