Re: Is my 258 knock-knock-knockin on heavens door?
I'd start with the person/mechanic/shop who rebuilt the engine. Unless that was you.
A mechanic's stethoscope can very quickly help you find the location of the problem. If it is coming from the valve train, it'll be pretty easy to pull the cover to see what's going on.
My '89 with 120k, leaks oil, burns oil, has little compression, runs 45lb oil, overheats, has two wrist-pins that have knocked (loudly) since 95k. I dont' want it to die, because like you, it's my daily driver. But sometimes I wish it would, then I would have an excuse to replace it.
Let us know if you can narrow the location down a little more.