Small Block & Big Block Chevy Specific - TPI 350ci spark plugs,help

Today I opened #1 spark plug and I noticed that half of the thread is black and the electrode is white(its platinum and .750" reach) and Im worried about it,My Camaro got MSD 6A,MSD wires and MSD coil and I want to know what causing the black carbon on half of the thread and the white thing on electrode and what reach is the stock spark plugs for TPI 92 Camaro iron heads?

124485 this is for l98 iron heads

124486 this is for l98 aluminum heads

see how much shorter the shank is on the iron headed plug? ACDelco # is CR45TS
you're lucky having the longer plugs in there didn't cause major problems

So now I cant use the car till I change the spark plugs right? but how is that the previous owner was using long thread plugs and nothing happend? when I changed the spark plugs to platinum I toke the part number and I went to auto shop and bought Platinum plugs and when I changed the plugs installed MSD wires coil and 6A I just felt a little difference but nothing in performance are long threaded plugs cause this? because my friend got a 91 Z28 with the same set up but a stock camaro hes kinda faster and we both run healthy engines

So now I cant use the car till I change the spark plugs right? but how is that the previous owner was using long thread plugs and nothing happend? when I changed the spark plugs to platinum I toke the part number and I went to auto shop and bought Platinum plugs and when I changed the plugs installed MSD wires coil and 6A I just felt a little difference but nothing in performance are long threaded plugs cause this? because my friend got a 91 Z28 with the same set up but a stock camaro hes kinda faster and we both run healthy engines

well apparently you havn't had valves or pistons run into the plug thats protruding into the cylinder too far, so its still driveable just get the right plugs in it as soon as you can, or leave them i dont care im just saying you have the wrong plugs in your car

well apparently you havn't had valves or pistons run into the plug thats protruding into the cylinder too far, so its still driveable just get the right plugs in it as soon as you can, or leave them i dont care im just saying you have the wrong plugs in your car

Thanks for your help

one last Q : what is the stock shank reach? is it .460 ?

i used autolite 26s for a very long time in my TPI
26s N/A and 100 shot
25s 125 to a 175