g'day Brewster , had the same game over quite a few years with my 66 convertible , new rad , then 160 thermostat , 5 blade fan , 6 blade fan then a 7 blade fan with shroud...which worked for most of the year but in HOT QLD summer it still ran" hot as" very quickly in traffic... as my car is NOT a resto , in the end I modified a large 17" Mercedes thermo fan with factory moulded shroud I hadta do a cut-n-shut but it now looks like a factory type install , I linked it with a thermo switch in the thermostat housing (via a kill switch) presto runs in the low end of the gauge all day automatically !!