351W oil pressure

[allen_cobra]

I have a 351W with 6000 miles on it and over the last year or so the oil pressure has been slowly dropping after a long run (40-50 miles). On short runs (15 miles) it seems ok, the engine is at temp (185) in both cases. Originally it was around 55 at 2500rpm and 30 at idle (850rpm). It is now at 45 and 18. I pulled the oil filter, cut it open (what a pain) and found some tiny metal flakes in it, about 1-2 per pleat in the paper filter.

I haven't torn into an engine since 65, so here is my guess
1. dist/cam gear wear and the oil pump is shot
2. something really bad is slowly happening

I really don't want to pull the engine unless I have to but if it is #1, change out the dist gear, new oil pump and ??
If #2 is it possible to change the bearings without pulling the engine?

Any other ideas? If #1, should I pull it anyway and replace all the bearings?
Thanks
Joe B