Thread: L-78 Spark plug choice
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Old 02-23-2008, 08:02 PM
Chevy454 Chevy454 is offline
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Default Re: L-78 Spark plug choice
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...
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