NGK TR6s and Autolight 103s are for boosted applications. They are a one step colder plug than normal. I wouldn't recommend them for a non-boosted application. Also, I once found Ford COPs for about $53 on-line. My mechanic has replaced two over the years. He charged me $80 each.
Fordy9er, didn't you have an intake manifold break about the same time as I did. My break drenched the entire motor in antifreeze. I had a bad miss and I had one COP replaced but I swear I still feel a slight miss sometimes. Other times not.
I have read that we need to take the boots off the COP and clean everything. I just haven't done it yet. But I think it would be wise to do that before buying all new COPs.
ProCharger P-1SC, 9 psi, STD 396/383; Uncorrected 388/375; SAE 383/370.
USAF 1969-1996: Vietnam veteran. Aircraft maintenance. ICBM Operations. Research & Development.