Same thing happened to mine, minus overheating. Around 155K miles. Its now at 167K miles. Fixed mine 6-8 months ago. I didn't even machine the heads. I should have, but I had a time crunch. so far, its been okay. next time it blows, it gets a compete rebuild to a 4.6L
The fire ring on the cylinder blew out. I replaced pretty much all the gaskets and seals on the top end. Took me about 10 hours in total with lots of cleaning. I replaced the valve seals as well and the head bolts. bought my kit from BPUtah.com for around $215. Its a Victor Renz kit.