You are running a 350 Chevy and I assume a carburetor rather than a computer controlled fuel injection system. Since you don't live in California you probably aren't running a catalytic converter or an O2 sensor. I wouldn't want to operate your engine at 160 degrees as that will induce sludge buildup. That said, there is no reason to have to operate it at elevated temperatures and have a small margin of heat tolerance in traffic on a hot day. I would continue searching for a solution.
I don’t know your normally driving but since you say it’s ok with exception of idle, I have suggestion. Start cold and Drain your tank down abut an 1” or so. Start the engine watching the water in the rad. With your heat gun watch to see when you are positive the thermostat is open. If you see no water movement in the radiator reach over and raise the rpm slightly100to200 rpm, maybe to the first fast idle on the carb high idle cam. If you see water movement put on a smaller water pump pulley. Fixed my idle heat up. I can sit at a long signal when it’s 90-95* no change. I didn’t have any water flow at idle....Good luck.
My 32 had a cooling components fan. I had an electrical controller and had the fan come on about 10 degrees after the thermostat opened. I also had an over-ride switch on the controller. Anytime I was in "parade" mode, I would turn on the fan. It's easier to keep the heat down than it is to get rid of it was everything is hot. This was in 100 degree temps also. That was with ac also.
I had a job once to size an oil cooler for an aircraft. I had all kinds of data on coolers. It is interesting in that the thick coolers cooled very little better than the thin coolers and required more ram air pressure. to do it. The thick coolers hindered the airflow and the down stream tubes did not do much because they were working in heated air fom the upstream tubes. New cars have very thin radiators.
I see no mention of how much timing in it and it has no vacuum advance Sent from my SM-J737T using The H.A.M.B. mobile app
How about some information other than it has a 350 Chevy in it Sent from my SM-J737T using The H.A.M.B. mobile app
Not sure on the timing, the engine has a small cam , stock heads , roller rockers , aluminum intake, Edelbrock carb,700r trans.
I run a constant bleed line from the from the top of the zip riser to the top radiator tank. I am building a 32 now. Will put a photo on tomorrow. Also, If the air can't get out of the engine compartment it can't get in. I don' think the air is getting out. Mine has never seen 210 in 100+ degree traffic.
Most overheating problems are caused by incorrect timing at idle or total timing need to correct that before you worry about other overheating problems Sent from my SM-J737T using The H.A.M.B. mobile app
The Jalopy Journal
