Spark plug heat range

Just pulled these plugs after 12 years in a survivor 440-6.
These are mopar p34
I guess equivalent to j11y

What's the prognosis?

Running a bit rich, heat range looks ok by the appearance of the ground strap

It's rich because I just start it up and don't run the car much.
I need to get it up to speed and heat more often. It's tough to get tge car out. It's always buried. Keeps fouling plugs.

If it keeps fouling plugs the way you are using it, a step up in heat range won't hurt. You really need to get into the habit of running it 1/2 hour after it reaches operating temp every time you start it. Right now you are really rushing it towards deuteration. Short runs after a start up for a motor that sits for long periods is actually just filling the motor and exhaust system with combustion acids that need to be burned off every time after a start up. Those combustion acids will eat away at everything they are allowed to sit in.

If it ever gets to the point its actually used again (or run it long enough to burn the combustion acids out of it), you may need to drop back to the colder plug heat range. Hopefully when you start it up, you are at least able to put it in gear while its on jack stands, and let everything in the drive train get to move. Gene

If this is the case then looking at the plugs isn't going to help. Sounds like you know what needs doing, drive it more.

Ground strap has nothing to do with the heat range.

https://www.ngkntk.in/importance-of-heat-range/

NGK's write up is for the lowest common denominator, they practically wrote it in crayon.

IMO overall the plug reads lean from mid to full throttle. I learned from friend and the man that invented the Lectron motorcycle carburetor Bill "Red" Edmonston that a spark plug is read by the ground electrode. He said that the first few thousands of the base of the ground electrode is the idle and first part of the carburetor setting or circuit and progresses up the ground electrode to the tip for wide open throttle. You stated that you start the engine and let it idle so that is the reason you see the black very rich condition at the ground electrode's base and outer thread ring, and even the center electrode. The rest of the ground electrode looks lean to me and may be because of too hot of a spark plug heat range rather than lean jetting IMO. Just my

Mike

100%

Looks normal to me. Back in high school we had to change the plugs on my buddy's 440+6 car every weekend before we took it cruising. Plugs got fouled every week driving the car to school. Back then it was just a $1200 used car. Ran pretty good with fresh plugs.