...I have Tested ALL the Autolite Plugs! 24 is too cold 26 is Too HOT and will cause Pinging in a 'Normal' running Engine. 25's are Perfect by My Testing!
You can go to Hotter #26 Plugs, but until You fix the Problem of Oil being sucked into EVERY Cylinder of That Bank, you're just going to be Burning Oil and Replacing Plugs!! ALL 4 Cylinder Spark Plugs Are 'Oiled', Equally!! There is NO Fix For it. I would Take the Manifold Off, I'll bet it's the Intake Gasket! Intake Gaskets are Very Tricky to get Right!!! They Eather Seal Correctly or It's Very Easy to get them Out of Place. On 4V Ports the Gasket covers less than 1/4" around the Perimeter Bottom. That is why I invented the '4 Stud' Guiding System, it Holds the Gasket Correct, while you drop the Manifold Straight Down! ALL of that Oil is NOT Normal! Yes! I Invented it! I first posted it here Many Years ago. Enough said.
How does the Other Bank of Plugs Look? NOT as Fouled, then it's the RIGHT Gasket. All 8 Plugs Fouled...It's the PVC Valve OR the Entire Manifold is Not sealing against the Valley, My Guess.
MJ