L-78 Spark plug choice

**Bill Rose** · #1 02-23-2008, 12:11 AM

What do you guys find is the best plug to use in the 69 840 heads. Someone mentioned NGK. I'm doing everything I can to keep the 69 L-78 ElCamino correct, but if there is a plug that works better than the AC's. I guess I can deal with that. Brand? Part# Where to buy?

**YENKO DEUCE REGISTRY** · #2 02-23-2008, 12:22 AM

Stash your NOS AC's in the trunk for bragging rights, but run the NGK's!

**Bill Rose** · #3 02-23-2008, 02:08 AM

I can't seem to be able to figure out which NGK plug (part#) would be used for a 69 L-78 application. I need a part number, so I can walk into an auto parts store, and order them from a 20 year old who thinks a Chevelle is made by Ford.

I found GR5, GR5GP AND GR5IX, for 69 L-78.... Any one know which would be the better one to use?

**Tommy** · #4 02-23-2008, 02:46 AM

Bill, If you have your AC number they can cross reference that on the computers (I work PT at Advance) and that will give you some NGK numbers. Believe it or not we still have books and catalogs behind the counters but alot of the newer/younger employees haven't been introduced to them. If you can get one of the guys/gals to pull the spark plug catalogs, they have lot of information about heat ranges and numbering systems. I sell a lot of plugs to racers, they buy several heat ranges and try different brands. I even go through boxes of plugs with one guy while he finds the ones that index the best for him. he is nuts.... But very fast... I will be at work tomorrow, PM me with some numbers and I will look up some stuff for you. I stock and can order the Autolite racing plugs if anyone needs them too.

Tommy (believer in the catalogs)

1968 nova ss · #5 02-23-2008, 02:52 AM

NGK,you want be dissappointed.the ac delco have had issues in the past;been there .chris teed

**Mr. Chevy** · #6 02-23-2008, 05:27 AM

NGKs are the ticket!!!!!! I had nothing but problems with the AC Delcos in my 396/375HP Motor, engine would miss at around 3,500 RPM.. The NGKs "woke up" the combustion chamber. Engine runs much better!!

I bought mine at the local parts store, Advance Auto Parts, and I think they were around a buck a piece.. Well worth it!!

Rich

**Bill Rose** · #7 02-23-2008, 05:47 AM

OK done deal. I went to Advance, Auto Zone and neither could find what I wanted in their comp or a book. I had to start by telling the "girl" that a Chevelle was a Chevrolet!! I just had to leave. I went to Google and found, what else but, Sparkplugs.com. They were shipped within an hour. Should be here ina few days. Thanks for the help.

m22mike · #8 02-23-2008, 06:54 AM

Base plug for L78 is NKG-2851, $2.38 @ Summit Racing the other day.
Mike

nuch_ss396 · #9 02-23-2008, 07:27 AM

OK guys!

While we're at this topic, what would be the correct NGK plug for a '69 L/89?

Nuch

NCGuy68 · #10 02-23-2008, 08:28 AM

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

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