Thanks for the replies everyone. I will check the PCV, is the reasoning that I am sucking up oil into the intake? I took the car to work today with cylinder 1 replaced (ac delco R43S) and also took a pic of cylinder 2 (autolite 85), I will eventually change them all but store did not have autolites though I prefer ac delco. So first pic is cylinder 1 with new plug and ride to work, it doesn't look like it is fouling to me anymore so maybe too many short startups from winter based on my first post. Second pic is cylinder 2 unchanged plug, look pretty much the same. What I"m also trying to figure out is if R43S is a colder plug and autolite 85 is a hotter plug, why is the heat line at the same location on both plugs. The store specified R43S for "conventional 4BBL" and R45S was listed as a second choice. Which heat range should I use? The motor is from a 1970 big car 455 so it has the #15 heads and an edelbrock 750 carb, edelbrock intake and headers.