PUZACTLY. What they wrote in 1969 about oil is absolute nonsense today.
It is 100% BULLSHIT and bad philosophy to keep telling people you have to slow the coolant down for more effective cooling. That is WRONG and I don’t care who writes that it’s not. I never gave a crap what any engineer says until I’ve proven it out. Chrysler was way, WAY out in front on their ignition stuff. Carb tuning too. I have to grab my 73 FSM to remember what it says, but IIRC all the 340’s and 360’s had overdriven pumps.
Now...let’s talk about how this works some more. I am of the opinion that the THERMOSTAT is what SHOULD set the MINIMUM OPERATING TEMPERATURE. who can argue that? I know one guy who will try. Minimum operating temperature is exactly what the thermostat is supposed to do.
Now that we have the thermostat to set the minimum operating temperature, we can talk about why a guy can use a 180 degree thermostat and have a cruise temperature of 190. Or 195. Or higher.
It is exactly because the cooling system can NOT dump enough heat to keep the MOT of the thermostat and the cruise temperature the same. They really should be. So when someone says “I run a really nice high flow 180 degree thermostat and going down the freeway my gauge says 195 and that’s where it should be because that’s not too hot” I say you are wrong. You are better off with a 195 thermostat so the minimum temperature is controlled by the thermostat and not the crap cooling system.
It’s simple really. And it’s pretty dumb to use a 180 or colder thermostat if you don’t want fix your cooling system so the split between MOT and cruise temperature is the same, or damn close to it.
The only ways I know of to make the cooling system more efficient is to make the radiator bigger. Then use two big cores instead of 3 or 4 smaller cores. Get an 8 blade impeller high flow water pump or a Flowkooler so you can move some coolant. Then get a Stewart Components high flow thermostat. There isn’t a better thermostat on the market. Not even close. The least thing you need to do is speed up the water pump. Go as fast as you can find pulleys. And keep the belt on. You can’t get too fast. I don’t believe you can cavitate the pump with any speed you can get from available pulleys. So speed it up.
If you do that, you can easily run a 180 degree thermostat and drive through downtown hell and not go more than 5 degrees over thermostat opening. I think if everything is right, including the tuneup, you can use a 160 thermostat and keep the coolant right there. If you have it all right.
Never, ever slow the pump down unless it’s throwing the belt. Don’t ever use anything but an 8 blade impeller high flow pump or the Flowkooler pump. Don’t cheap out on the thermostat. Quality is quality. Get the biggest radiator you can fit with no more than 2 cores. And the 2 cores should be as big as you can get.
Do that and you won’t mind driving through hell.