You had the same experience that a lot of racers and hot rodders have, they don't hear it until the motor quits or starts smoking
![whiney whiney](/ubbthreads/images/graemlins/custom/whiney.gif)
I learned to look at the plugs frequently until I knew the tune up was safe
![up up](/ubbthreads/images/graemlins/custom/thumbs_up.gif)
On my stock 415 HP M.W. on the old 100+ octane high lead pump fuel in 1971 to 1973, it liked the stock J11Y, not the J10y or the hotter J12Y spark plugs. I could hear the difference in idling right away, I could see the differences in on the plugs with one full WOT blast down the street
![work work](/ubbthreads/images/graemlins/custom/work.gif)
As far as heat on the plug tip the center porclyn determines what the tip temperature will be, retracted or projected
More porclyn around the center electrode less heat transfer
![work work](/ubbthreads/images/graemlins/custom/work.gif)