what does the bottom of the head look like, I'm betting the valves for that clyinder were demolished as well...
I had a similar incident happen w/ my prior 94 Bronco... after buying it from a mom & pop dealership, 30 mins into my ride home @ 60mph, there was a horrendous, loud -BANG- proceeded by a dense Spy Hunter smoke screen behind the vehicle, followed by metal particles hitting & bouncing below the truck onto the highway and a continuation of what sounded like hundreds of metal pots & pans being banged around... Eventually I coasted off to the side of the highway, had to have a State Trooper come to assist so I would not get slammed by approaching vehicles since I was a sitting duck and had to wait for a flat bed service. When bmwpower and I finally removed the 5.0 engine from the truck and started disassembly - there was NOTHING salvagable from that engine at all...
The crank looked like someone stuck the journals in a blender, the #4 and #8 cylinder walls were completely "chiseled out" and gone about half way up the block, the rods to both the #4 and #8 pistons were completely sheered off from the crank, both rods were all bent, there was a nice hole in the oil pan, the camshaft was also torn up from all the detonated metal particles washing around inside the engine, tons-o-metal chunks in the oil pan and the valves & combustion area on the bottom of each head were also slightly damaged.
So, yes, I too can relate to a slight, unexpected highway "detonation"...
