I don't know why I'm joining in but here goes.
First, the notion that you need a thermostat to slow down the water so that heat exchange can take place is utter BS. This wives tale has been around for ever, and won't die. Even if the water goes through the radiator twice as fast and only loses half as much heat, it is also going through the engine twice as fast and removing half as much heat. A little algebra (I know math) tells us that since the equations balance, the total amount of heat carried away by the coolant is the same.
The notion that you need this restriction to send water to the rear cylinders is also BS, mainly because as others have pointed out many have run without restrictors, or thermostats without cooking the rear cylinders.
There are many excellent reasons you should run a thermostat, sending water to the rear cylinders, and actually causing overheating is not some of them.
Finally, as far as the pinging goes, it is clear that there was too much spark advance at an improper time. I disagree that the answer is simply to disconnect the vacuum advance. As vacuum advance is designed for those situations in which you are operating under differing loads. The vacuum advance should be considered a load advance as it increases the advance with load largely independently of RPM. Good vacuum advance can help eliminate or mitigate engine bogs under load. Having someone go through the distributor and having it curved would be a good idea. Good vacuum advance makes a car more responsive and fun to drive.
Temperature and engine wear. If you were to graph engine wear vs. temperature you'd find that wear increases hugely as temperature DECREASES. Engine wear at 160 F is approximately 4X that of 180 degrees F. Engine wear at 200 F is even approximately half that of 180 degrees. Obviously when engine temperature exceeds a certain point other problems arise, parts expand too much, oil breaks down and loses it's protective properties, and engine damaging detonation can occur. This is why most late model cars have 195 degree thermostats from the factory as it is good balance between wear and performance. Today's engines easily last for 200K miles because they both run hotter and better engineering and better tolerances. For example todays high silicon aluminum pistons expand a lot less than earlier pistons which allows for tighter fitting pistons longer life.
Hot-rodders figured out years ago that running at 160 degrees was good for some additional horsepower, but this was at the expense of MUCH greater wear. In my opinion for a street driven hot-rod a 180 degree thermostat is a pretty good balance between increased engine wear and performance.
Remember the golden rule (no not that one), don't put a bandaid on you elbow, when you have a skinned knee.
Regards,
Joe Dokes
