502 carbed spark plugs
04-09-2003 | 07:01 PM
#1
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502 carbed spark plugs
I need some help please! I just purchased a used 97 baja boss with a built 502. Im going to do a tune up here soon and want to know what spark plugs are best for this application. It is a performance built engine close to the 500HP(?) specs, around 500 hp and 575 lbs-ft and has a carb. The plugs that are in it are Champion RV15YC4 and look to have worn normally. Any one with a carbed 502 out there have any suggestions? that would be great. thanks Derrick
04-10-2003 | 03:44 PM
#4
Charter Member #1171
Joined: Feb 2001
Posts: 4,018
Likes: 21
From: Clearwater, FL
Originally posted by Griff
AC Rapid Fire #1's worked very well for me.
AC Rapid Fire #1's worked very well for me.
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I want to live in a world where a chicken can cross the road and not have its motives questioned.
I want to live in a world where a chicken can cross the road and not have its motives questioned.
08-05-2004 | 11:28 AM
#5
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Joined: Jan 2001
Posts: 37
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From: cleveland ohio
Re: 502 carbed spark plugs
Originally Posted by convincor
Not sure with your application, but i've had real good luck with Bosch Platinums in mostly stock engines.I use them in everything i own.
Found a conversion chart that list all brands if you need it.
Found a conversion chart that list all brands if you need it.
08-05-2004 | 12:24 PM
#6
Official OSO boat whore
Joined: Oct 2000
Posts: 6,157
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From: Mequon, WI
Re: 502 carbed spark plugs
A MR43T is a very popular marine plug. I too run the platinums in my street vehicle, but I havn't been able to cross reference to a marine plug. The MR's have a stainless body so they won't corrode.
08-05-2004 | 03:17 PM
#7
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Joined: Mar 2004
Posts: 726
Likes: 10
From: Miami, FL
Re: 502 carbed spark plugs
DENNIS IF THE ENGINE HAS GM IRON HEADS OR EVEN MERLINS WHAT I USE HERE AT THE SHOP ARE NGK YR5 THIS IS THE PLUG I USE EXCLUSIVELY AND WE BUILD ABOUT 2 ON A MONTHLY BASES WITH NEVER A PROBLEM WITH THAT PLUG. HOPE THAT HELPS LAZ MESA WWW.MESABALANCING.COM,
08-05-2004 | 08:15 PM
#8
Charter Member #818
Joined: Jan 2001
Posts: 644
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From: West Michigan & Higgins Lake
Re: 502 carbed spark plugs
Those Champion plugs will work just fine. They have an extended tip so they will not foul easily if you do a lot of idling. I have them in my 502 and they work great. I doubt if a more expensive plug will make any difference in how it runs.
08-06-2004 | 12:57 AM
#9
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Joined: Jan 2002
Posts: 194
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From: HARRISON HOT SPRINGS B.C.
Re: 502 carbed spark plugs
What about plugs for aluminum heads.I have to use the ones with the small hex or I can't get a plug wrench on them.Even with the small hex I had to make a custom machined down socket with a universal tig welded to it.I have used champion rc12yc an ac fr3ls.I like to change my plugs a couple times a season just to monitor whats happening in the engine.I have not had any real complaints with either plug.I would like to try a colder one because after a hard run I sometimes get a bit of run on at shutdown.
09-15-2025 | 07:43 PM
#10
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Joined: Mar 2025
Posts: 11
Likes: 1
From: Dubuque iowa
1990 baja 250
just curious what spark plugs i should be running in stock 502 jasper motor in my Baja? right now i have NGK R (BR6FS) plugs. Had dads friend who is mechanically inclined that he doesn't think they are right, it thinks i should be running NGKUR4? any input on what i should be using?
