I have searched but can't find much on this...

I have a 91 S10 blazer, and NGK plugs are usually my plugs of choice, however I got Autolite cheap ones recently...

how is it that the "Reach" of the plug (length of threaded section) is at LEAST 1/8th of an inch, maybe even 1/4 inch longer than the NGK equivalents...shouldn't the reach be the same?

Either way, not surprisingly, the autolites suck

 

Here's a link to the NGK Plug, the correct size for your engine. The "Reach" shouldn't be over 5/8". Some really smart parts guy may have given you the wrong plugs.

http://www.sparkplugs.com/more_info.asp?AAIA=&pid=2670

 

That's what I was thinking. I appreciate the response.

I will never break my "nothing but NGKs" rule ever again LOL

 

i hate to resurrect this thread from 13 pages ago but i have the exact same question and wish to clarify it.

i'm in the opposite situation of the OP, i've always used delcos and just now wanted to try the ngks, but i've noticed a marked difference in the size. they both have the same thread reach (which is 11mm, by the way, 5/8s is the hex socket size) but the ngk iridiums are a lot shorter than i'm used to.


the ngk and delcos were both found with their respective parts applications and i clarified the parts numbers at a local parts store and sparkplugs.com so i can rule out "parts guys are dumb", they're both "correct".

are people using those ngk iridiums without issue?

 

I'm running NGK iridiums in my 01, have been for about 10K miles with no problems.