I am wondering how fast a valve seal can fail on a 72 m130v with 96,000 mi.

I had her running great the last few weeks, an I even cleaned out the fuel tank last week. But in the last two days the #1 cyl. started to miss on startup but would go away after about 30seconds of running. Yesterday it began blowing blue smoke and the plug is covered in oil this morning.

I did a pressure check and it is 150psi - I am thinking that one of the oil seals failed.... but is seems so dramatic of a failure considering that she never burned any oil in the past.

What do you guys think?