Calling All Spark Plug Experts, Opinions on these pics.

don't think an injector issue

Either ignition or engine oil fouled

Or both

Easiest ignition wires, coils, plugs. I do NOT recommend going hotter on any
big block...especially towing heavy like you do. Colder is more like it

Really think engine oil mist and/or stuck ring. Either compression ring and/or
oil ring allowing engine oil to get past them and into the combustion chamber

Why and still say to put in new plugs/wires/coils and make some high throttle
runs for a full tank of fuel

Ok, no PCV. EGR?