Ok, I have been reading several threads that describe a similar problem as I am having. I have a 79 Bonneville (obviously) and it has the 350 Buick in it. This car gets warm at highway speeds. I replaced the head and intake gaskets. Running around town she stays at about 210. I have a 190 degree thermostat in it. It seems to build a lot of pressure in the upper hose, and not so much in the lower hose. There is about a 30 degree difference in temperature between the two hoses (190 upper 155 lower) the block is registering at 250 plus. I'm having issues seeing the timing mark, it seems that unless the distributor is completely retarded, the timing mark doesn't come close to 15* btdc. I also replaced the vacuum advance thing on the distributor. I'm lost, is it a timing issue, carb issue, radiator issue? It does everything the same as it did before the gaskets were changed. No I didn't have the heads checked as it never got over 250ish... like I said I'm lost!