[elmariachi]

So what solved it, the higher pressure cap or the burp?

The 160 vs 180 argument never ends. Personally, I see little use for a 160 except for the fact that it opens quicker the first time and affords that much more delay (maybe minutes at best) before your temps climb on up to operating temp. If you run a 180 or something closer to the actual operating range of the engine, then the t-stat may have a chance to actually close from time to time, allowing time for the coolant in the radiator to cool further, thus promoting a better "cooling exchange cycle." Then there is the argument that 160 is too cool for an engine to operate. It certainly is for an FE. But in my opinion a 160 t-stat is just a gate that opens once and never closes on most engines, so it doesn't really effect the overall operating temp anyway.