Spark Plugs What is wrong?

[53chevyforever]

Originally Posted by Grumpy old man

I would get a correct set of matched plugs gapped correctly and run it again before you get too crazy trying to diagnose whats wrong , the threads don't even look the same length let alone the heat range can't be the same .

I had all the same at first...they looked fouled so bought all new ac plugs at beginning...no difference...then this last try...I put in the 3 autolites...still ran the same.