For the last several years my 164 has had some problems with overheating at highway
speeds, especially in hot weather. It is a bit unusual in that it has the 3.31 differential
AND overdrive. It has dual SU HIF6 carbs, clean radiator, no constriction in the
exhaust, and adequate ignition advance. I rarely use the overdrive. At 50 mph it
cools beautifully but at 65-75 it gets hot pretty fast. I have been through the
entire cooling system and even pulled the head and gave it a valve job (which it didn't
need very badly) but it still does it. Mixture may be slightly on the rich side but
it runs well, no black smoke or stinky smell.

Today I happened to notice a B30 water pump pulley next to one from a B18/20.
The B30 pulley is somewhat larger. The B30 water pump is also somewhat larger.
Do you suppose that it might be helpful to put the smaller pulley on the bigger
water pump to get a little faster circulation? Because of the 3.31 gear, the
engine speed is fairly low and I think maybe the pump would be more efficient at
a higher speed. What do you guys think?
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George Downs, Bartlesville, Heart of the USA!