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Spark plugs for 454?

I have always had good luck with plain ole cheap Autolites. That's what I'm running in my 540 too. Never cared for champions. Acdelco always work well too. Don't worry about double platinum unobtanium coated. We change them too often to worry. Just anti size the threads and you are good to go.
 
Don't do the A/C Delco they don't last in marine engines. I put them in Brian's 7.4's 2 years ago and both engines had a slight miss late in the season. I replaced last year and it was still running great late season. I'll have to ask what went in, I can't remember right now. I think NGK but I need to double check.
 
RNGRDVE said:
Don't do the A/C Delco they don't last in marine engines. I put them in Brian's 7.4's 2 years ago and both engines had a slight miss late in the season. I replaced last year and it was still running great late season. I'll have to ask what went in, I can't remember right now. I think NGK but I need to double check.
Click to expand...

Ahhhhh!!!Don't tell me that. I pick up some ac delco mr43t for mine last fall. Haven't installed them yet. We will see how the hold up this spring.
 
You may have different results but the guy who ran the marina where Brian kept the boat said never use the delco plugs. Of course that was after I played contortionist on the first set. Twins suck to work on.
 
I usually run autolites on anything 4 stroke and NGK on anything 2 stroke. NGK makes a great plug too. Autolite AR3933 is what most aftermarket BBC heads take like my AFR's and old Dart's.

On the 8100 Vortec/496 MAG motors, the only thing to use is stock ACdelco's. They are extremely sensitive for some reason. I learned that the hard way haha. They aren't cheap either.
 
I had NGK in there. I only went to the champion plugs because the NGK were not available here in town the day I decided to change them. Looks like I'll be switching back.
 
don't know if things have changed but when i was in the business mercury only recommended ngk plugs. however, mercruiser engines all came with ac from the factory.
 
Not being 454 specific here, but I like NGK in m Mercury and foreign vehicles. I usually use Autolites in my Ford and Jeep CJ. Chrysler vehicles seem to like Champion plugs.
 
really? what year is it?

i left the biz in 2005, everything to that point was ngk br6fs for the older engines and i believe it was bpr6fs or maybe bpr6efs i can't remember for sure but they were the mpi engines with a long reach. the br6fs was a short reach.
 
Matt, my engine cover calls for Champions too. But in the decades since the boats were built there have been a lot of improvements in technology. I have been on the NGK bandwagon since Tyler Crockett told me to run them. If I said how long that set has been in my motor I would get flamed! Try them.
 
I was lying... I just checked and it calls for the AC Delco AC-MR43t.

I thought I put Champions in there. Damn I have no clue what's in there now. :shakehead:

There will be NGK's in there soon though.

So for the 97 carb 7.4L I should run the BR6FS?
 
illMATTic said:
I was lying... I just checked and it calls for the AC Delco AC-MR43t.

I thought I put Champions in there. Damn I have no clue what's in there now. :shakehead:

There will be NGK's in there soon though.

So for the 97 carb 7.4L I should run the BR6FS?
Click to expand...

Had a set of AC, but made the switch and just put a fresh set of BR6FS in my 97 454 Mag. Best price I found was at Wholesale Marine. $1.88 each. Ordered box of 10 and got them in a few days.

http://www.wholesalemarine.com/ngk-spark-plugs.html
 
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