I was supplied autolite spark plugs for my 99 camaro that cross reference only for 97-98 LS1s. 99+ LS1s LS6s etc seem to use a different (same size) spark plug. Anyone know what changed in 99??

thanks

 

just thought I'd mention...

According to the Autolite lookup, the 97-98 LS1s should have Autolite APP104 and 99+ LS1s and other LSx until 2008 etc use Autolite APP5245

I was incorrectly supplied APP104 for my 99 car but they are telling me they are OK.

Does anyone know the reason 98 and earlier and 99 and later LS1s have different spark plugs? I can't find any info about this anywhere.

 

Interesting- what does Autolite (Ford!#$!) say about the difference in those plugs? Differing heat range, maybe?

Platinum to last long- remember, they had to pass emissions for 100 k miles-

What did the factory install, AC Delco? That is what is shown in my parts manual-

 

thanks... it still lists different equivalent Delco plugs for the APP104 and APP5245.

The only difference in the specs I can see, 104 is "power tip" the later one is "super power". Usually I'd think the newer plug was a newer design but they still list the 104s for the 97-98 LS1s so I'm thinking there must be some kind of difference in the ignition system since 99 (but I've never seen any mention of this anywhere)...

APP104 delco equivalents:
41-810, 41-913, 41-931, 41-937, 41-947, 41-948, 41-950, 41-987

APP5254 delco equivalents:
41-805, 41-908, 41-928, 41-974, 41-983

Here's the info I got this from... (I've found similar info on other websites but no reason...)

http://www.power-21.com/honeywellpow...?b=A&pn=APP104

http://www.power-21.com/honeywellpow...b=A&pn=APP5245