Need some opinions on spark plugs

[moparmaniac10]

I'm in the middle of building my 440 for my 71 challenger and have gotten to the point of the spark plugs. My engine is close to around 400 hp with a mild cam, aftermarket intake, mild port job on the stock heads, 750 Holley, and headers. I was just wondering what people would suggest as a brand of spark plug to go with in the engine. I'm sure there are alot of people out there that have tried many different kinds and liked or disliked some. Give me your opinions and a part number if you got it. Thanks.

 

[moparleo]

Mopar always used Champion spark plugs. J12Y, RJ12YC, RJ14YC

 

[ramenth]

This is like asking opinions on engine oil. Everyone has a preferred brand and are loyal almost to a fault. No one's right, no one's wrong, and everyone has an opinion, usually based on personal experience with no empirical evidence to back it up.

I usually stick along the lines of manufactures for plugs. Champs for Mopars, Delco for GM's, Motorcrap for Fords, NGK for Asians, and Bosch for Europeans.

No room for Autolites. I know of guys who have had good experience with 'em, but I haven't. I've seen too many cars come into my bays where someone has put in a set of Autolites and the car starts throwing a misfire a couple of thousand miles later. Pull the plug and the ceramic is broken. Again, that's my own personal experience. Other's may vary.

 

[Chryco Psycho]

In a dyno test with a SS Hemi we wanted every single HP available ,cost was not a deterrent , almost exactly the more the plug cost the more power that was .................... LOST not gained , the cheapest Champs & Autolites made more power & the more we spent with Iridium / Platnum / multiple electrodes / V grooves etc the more power that was lost . So in reality it is not like oil so much most oils meet requirements until SL & newer oils which is a whole other discussion we were able to prove results factually .

 

[ramenth]

So in reality it is not like oil so much

Actually, what I was pointing was that usually most who have an opinion have no empirical evidence to back up that opinion. For a lot of times it's brand loyalty. A "feel" for what they think is going on.

How many times have you heard or read guys say they put Brand A in their daily drivers, replacing Brand B plugs and "it's running so good I'll never go back to Brand B," without thinking about what they've just stated. Of course, Brand A plugs are going to be better when Brand B plugs when Brand B plugs have been providing spark for the past 100,000 miles. At that point, just about any plug is going to do better than the tired old worn out ones.

That's where my comparison to motor oil was coming from.

Like I said, I've had bad experiences with Autolites, usually in the reliability issue. I've heard good things about them in a performance applications, on 1/4 mile at a time. But since my customers aren't driving a quarter mile at a time, I have to worry about longevity issues, too, to ensure the car isn't coming back before the next oil change with yet another misfire associated with broken plugs.

 

[Chryco Psycho]

I can understand where you are coming from just harder to prove the value of a given brand of oil !
There is some truth the other way too , the plugs that make the best power may not last as long in day to day street driving but if maintained properly should make the best power / milage / effciency

 

[moparmaniac10]

I ended up buying champions. Now I am just waiting for my MSD wires to put it all on.

 

[moparleo]

Use plenty of dielectric grease on the plug and cap boots. Water tight and no sticking to plugs when time to replace.

 

[ramenth]

Use plenty of dielectric grease on the plug and cap boots. Water tight and no sticking to plugs when time to replace.

A must.

I like to just a bit of high temp never seize on the thread's too.

 

[moparleo]

Thank you for reminding me. Absolutely correct.