Post a picture and we can decode it later. 3 hole gasket. https://www.rockauto.com/en/catalog.../+thermostat+housing+/+water+outlet+seal,2136
Replace the radiator or have it cleaned at minimum. It can’t possibly be 47 years old and not at least partially clogged. The ignition timing from the factory is all wrong. It hamstrings the engine and makes it run hot. Initial timing has to go way up and the vacuum advance has to be checked and set up so it is full time. If you are unfamiliar with working on the car, have a mechanic do it for you.
If all that was set at the factory and assuming it is all correct and working why does it need to be fussed with. I am not racing the car or the like. Seems to me factory worked in the day why not still work as designed. I suspect you guys that work on these, know the in and outs to make them be at their best. I find it hard in stock form this car can't roll down the road and not function correctly. I am not trying to say you are wrong with your suggestions just seems it could run as set up.
The original distributor should have part number 1112109. The part number is on the circumference of the distributor right below the cap. If that is the part number, set the initial timing to 12*. Then the vacuum advance needs to be hooked directly to the carburetor. It also needs to be checked with a timing light to make sure it still works.
Emissions regulations of the time led Buick to set the car up for that. It also made the engine run hot. Buick knew that and set up the engine to cool itself down if it got beyond 220*. Very hard to explain to someone with no automotive experience. If the vacuum advance canister isn’t working, it will make matters worse.
If it is set up just as it was from the factory, it will run just fine, but it will always run very hot, probably about 200-210*. Of course without a temperature gauge, you would never know it, but in the hot weather, it will be right on the edge of overheating. You are seeing signs of overheating so something isn’t quite right. A 180 or 160* stat might help some or not, depending on what is wrong. You are missing a lot of power also because of the timing but you don’t miss what you never had/experienced. Do what you are comfortable with and see if it helps. I have been on this board for 17 years and have seen this before many times.
See my post #14 in this thread, http://www.v8buick.com/index.php?threads/tcs-removal.329827/#post-2765925
If the vac advance was not working wouldn't I feel that in some matter, not starting well, running like a dog till warm, throttle response when driving from a stop, getting on it, etc? Sorry for what prob seems like dumb questions to you all.
No, you wouldn't notice it at all except maybe reduced gas mileage. In my experience, no. They develop white scale deposits inside, actually a reaction between the coolant and solder used in the radiator construction.
So in a nutshell I am looking at multi ways that could be making this car boil over. The timing and checking the vac advance the only things I have never messed with. I have fam members that know all that stuff, guess I need to offer to Pizza and have them over. I don't trust the car to drive on the HWY to get to their homes. I guess I can hit the easy stuff, rad cap, tstat and see what that does. I am told if I pull the lower rad hose I can see into the WP and see the fins, see if they are worn off? Maybe this is being over thought at this point in the game.
What is the little vacuum thing doing that is on the front right of Tstat housing doing. Looks like vac from dizzy goes to it, then a hose from it to the carb? Can that device just be by passed and run vac adv from dizzy to carb? What is it being power by electric doing?
that is the TCS, the Transmission Controlled Spark emissions system. This is the page describing it in the 1972 Buick Chassis Manual, And yes, you can bypass the whole thing and run one hose from carburetor to vacuum advance.
