OK, I'm going to have to say it again - because I see a pattern developing here.
EVERYONE I have ever personally known with a classic car overheating problem seems to have experimented with electric fans and found relief finally by going back to a good 'ol HD clutch fan and shroud that the factory designed for their car for A/C or HD cooling applications. This has crossed different makes AND models of cars, too.
I have seen this enough times that I would never consider electric fans as a potential solution. I just do not see how 12 Volt electric fans can come close to pulling the CFM of air like a belt driven metal fan.
I'm in agreement on this one. I'm running a 73 455 bored .30 over. I run a stock radiator, stock clutch fan, and shroud and stay at 180 degrees all day.