I did a search on the subject recently and didn't find much, glad you brought it up.
I WAS going to get additional pusher fans to augment my single puller, guess that idea doesn't work! Then I thought I'll increase the rad cap pressure from 13psi to say,,,,,16? But I don't THINK that will help either. Water boils at about 250 Deg F at 13psi so "boil over" isnt' an issue.
I run dead on 180 Deg F when on the highway. In town it will go up to 190-200 fairly quickly in stop and go traffic. In REALLY bad stop and go (try WAIT) and a HOT HOT day it got up to 220+.
I think "base timing" being "retarded" to much at low engine rpm may be a contributing factor to heat buildup.
I figure it like this: Todays cars run 190 t-stats, so 200 or so gotta be "OK". Even 220 isn't "that bad" as long as boil over doesn't happen. I'd rather NOT see that high but I don't think it's hurting the motor.
HERES the problem as I see it:
The carb fuel boils over! At high temps the motor can run leaner than at colder temps. Now the motor WANTS to run lean, but the fuel is boiling and the mixture becomes RICH. Plugs start to foul, possibly the extra fuel is washing down the cylinders and diluting the crank
oil?
One CC member mentioned he carried a piece of "foam" to prop the hood open and inch or so when he was doing "parades" or got caught in "stop and go". Fuel boil over was HIS complaint also, I assume letting the engine compartment heat out helps?
I'm gonna try that next time I'm "cruising" Waikiki and get stuck in traffic. Wait,,,,,, I aint cruising Waikiki anymore, as I WILL get stuck in traffic!
13psi cap, 5 core copper rad, 16" puller fan, 180 T-Stat.
Radical motor that wants to RUN, not walk.