What was happening those last miles is there was NO action on that cylinder that was hosed, there was no compression and all the fuel went unburnt or burnt sporatically from hot metal and the friction going on in there. The plug was probably for sure destroyed making it even worse.. you were then blowing fuel through the hole in the piston onto the ring and into the oil, it then ate away the bearings which started to overheat as the oil/gas mix started to lose lubrication properties and became basically a solvent REMOVING lubrication. Any time you pushed air in it hard *like boost* it was pushing that pressure into the crank case and causing all kinds of crap.
It then finally gave up in life and died as it seazed and the rod broke.
That would be my quick guess at what happend over it'* last 30 miles.
Glad things are looking up though. SOrry I didn't call tonight, got side tracked. I'll be PM'in ya shortly.