need help spark plugs (pic)

As long as the seat is in the same place, you're fine.

It will stop when the seat meets the head.

one looks like its for a gt-40 head the other for a stock head

yep as far as i can tell

TAKE THEM OUT NOW!!!!! THE THREAD COUNT MATTERS!!!! i had plugs that were the same size as the 1s on the left and my car ran like ****!!! and i was changing out plugs every couple of weeks....for the first week or two it ran ok...and then i had a bad bogging problem around 2500-3k...i changed everything...i thought it was fuel, so i cleaned the injectors, was already in the process of changing the fuel rail and lines so did it n e ways...took down and cleaned out the fuel tank, changed the fuel filter the whole 9 yards....still breaking up, changed the coil, still breaking up changed the plug wires, no good...reset the timing...idled better, but still breaking up...by this time i was ready to lake it and collect on insurance...but then rememberd i only have PIP...lol...finally i took the plugs out and asked a shop near by if he knew what was going on and he said ya...wrong size plugs....even tho the heat range is fine the thread count is off...the plugs screwed in just fine...but i garenty (how ever u spell it) that cyclinder #3 and #4 on ur driver side and passenger side will go first...and when u take them out in 3 weeks they will be brown as hell with the smell of gas...i put my car on it...i took the ****ty plugs out and put in NGk RU5s...the work perfec...

ps- sorry for the novel

the one on the right is good

the one on the left is BAD!