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Performance Spark Plugs vs AC Delco Stock

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Old 12-15-2009, 09:58 AM   #1
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Performance Spark Plugs vs AC Delco Stock

Happy Holidays All !!!!

I am looking to change the Spark Plugs in my 1985 5.0 Liter 305 Chevy Engine. Currently have installed the AC Delco Platnum Spark Plugs.

Car is not currently Raced at all, but I do like to burn some rubber here and there

There are so many Spark Plugs out there from Accel to Denso to NGK, what would you guys recommend and why.

Just looking for the best performance plug I can find.

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Old 12-15-2009, 11:20 AM   #2
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Re: Performance Spark Plugs vs AC Delco Stock

I personally would run the factory style AC delco's.....I don't believe that they make that much difference spending the extra money on those 'fancy' plugs. I even run stock style plugs in my built motor, it made the most power on the dyno with stock plugs. Just my opinion. I work at a shop, and see a lot of driveablility issues with different vehicles when they put aftermarket plugs in, instead of factory.
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Old 12-15-2009, 06:00 PM   #3
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Re: Performance Spark Plugs vs AC Delco Stock

Stock Delcos.You'll never know any difference in any plugs,because in a stock to mild engine,any improvements from a spark plug alone would be so minimal that you'll never notice it.
If I were to recomend a budget upgrade in that area,it would be an MSD replacement coil.And that,too,would only be barely noticable if at all.
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Old 12-15-2009, 06:38 PM   #4
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Re: Performance Spark Plugs vs AC Delco Stock

All the "gimmick" plugs do is make your wallet lighter. A proper AC/Delco plug in the correct heat range will work just as good. Don't believe the claims from all those fancy plugs. If you did dyno testing with all new plugs in different brands, it's unlikely you'll see any performance difference. Claims of power increases by changing plugs will happen even if you take out the old, worn out plugs and replace them with new plugs of the same make and brand.

I run NGK race plugs in my race car. They're about the same price as a street plug but they're built a little differently and have a wider selection of heat ranges.

The only benefit of platinum plugs over regular copper is that they last longer. A typical copper plug should be replaced about every 2 years. Don't even bother cleaning and regapping, just replace them. Platinum may run around 5 years before needing to be replaced. On some cars, changing the plugs is so difficult, it's worth the extra money to use platinum plugs.

The best thing you can do to get performance out of a plug is to make sure it's the proper heat range. So many things can affect what heat range the engine needs, it's trial and error to determine the best heat range for your engine. Timing, jetting, fuel type, compression ratio, power adders etc all determine what heat range it should be. If you don't know how to read a plug properly, the rule of thumb is to run the coldest plug possible that doesn't foul up. Too cold and the plug can't burn off the deposits. Too hot and it melts the electrode.
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Old 12-16-2009, 08:31 AM   #5
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Re: Performance Spark Plugs vs AC Delco Stock

I put E3's in my LB9 after seeing them dyno tested in an LS1 on powerblock. I know someone is going to rip me for buying into the "gimmick" but whatever. I actually decided to try them out because I was skeptical and they were only a dollar or two more than ac delco's so I figured what the hell. I was switching from ac delco rapidfires by the way. I have had them in for the better part of a year now and couldn't be happier. There isn't much difference throughout most of the normal driving range but I can definately tell a difference at high rpm's. For the minimal difference in cost I definately think they're worth it. I probably won't use anything else. I've got a jeep that uses NGK's but in about 10,000 miles I'll be trashing them in favor of E3's.
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Old 02-19-2010, 04:02 PM   #6
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Re: Performance Spark Plugs vs AC Delco Stock

Dose AC-Delco make different heat ranges? I think I need to step up a bit.
They have rapid fire #1 and rapid fire #2 whats the difference?
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