L-78 Spark plug choice

[NCGuy68]

Try NAPA. Forget about Advance, Carquest, Pep Boys, etc.....

[Keith Tedford]

I've always run the AC43N plugs in our L78 with zero problems. About 20K miles on the last set. NGKs lasted in our old snowmobiles when nothing else would. Everyone who uses them like them.

[Chevy454]

Sorry I'm late to the party...maybe I need to make an NGK plug reference post a sticky? LOL!! Anyway...

5671 is the gasketed plug for the 840 head ('69 & earlier)
UR5 is the tapered seat plug for the 291 head (late '69 & later)

I run a 5671-7 in our Camaro...the -7 part is the heat range, and NGK plugs are rated backwards of most plugs in that the bigger the heat rating number the cool the plug...Autolites are 'ok' plugs, but stay away from Champions or AC's...

[SSjeff427]

Autolite number 26, never had any problems ever. Not only is it fun to watch the "counter information engineer" look up a 69 chevelle 396 375 horse, try telling them it has a 427 and watch the fireworks.

[firez]

While we are on the spark plug subject,what about a 1968 302 Z28 plug ?

[Chris396]

What about the 842 aluminum heads?

[Mr. Chevy]

I even run the NGKs in my jet ski which is a two stroke motor. never had any foul yet!!!

Rich