Here's the run down. I bought a 91 bronco xlt with the 5.8. It had been sitting for almost 4 years. The previous owner broke one of the bolts off for the thermostat housing inside the lower intake manifold. The owner didn't know what he was doing and destroyed the manifold when trying to drill out the bolt. After that he parked it in barn yard for 4 years until I found it. I put a new lower intake manifold (got it off a 351 lightning) on it and got it running enough to get it on the trailer. However I did spend some time trying to drive it around the barn yard. While doing so, I found that it was burning coolant bad. It was beyond just the white smoke it was the white milky stuff coming out of my exhaust, also it would stall out and die if it went past idle speed. So I assumed that I must have messed something up when I replaced the lower manifold. I took everything apart to do the procedure again. I expected to see something wrong, but everything was perfect the gaskets had nice even compression marks on them. I started examining everything and I found traces of coolant all the way in the upper plenum from the number 7 cylinder. I went ahead and took the head off and again everything looked normal. I'm kinda lost on what to do next. Any help is greatly appreciated.