In your opinion what are the best spark plugs?

And what gap is it for the 4.8?
I've heard a lot of good things from the ngk tr55's

 

im running tr55s gapped at 55. im a 5.3 however but i dont see what it really matters. what mods do you currently have/plan on? any boost or spray?

 

Naturally aspirated I like the factory plugs. The fine tip stays cleaner and they last much longer than anything aftermarket. If you are looking to gain power with the swap look elsewhere. All the splitfire and e3 do is cost you money.

 

tr55s are very popular here

 

Lol well right now I'm doing the engine swap so no mods yet but i plan on doing the basics for now, cam, exhaust, tune and that's about it till i save up for T-56. Then ill start doing more.
as for the boost... Idk i might just do a dry 50-75 shot. I might go more once i swap the push rods and lifters but this is in the far future

 

TR-6 is the colder plug....its good for nitrous and boost so say. i run TR55 in my wt and TR-6 in my CC

 

Gapped to what?

 

Since the plugs in the truck are easy to get at and change, I have been keeping copper core plugs in it... they're cheap and I believe they offer the best conductivity. I feel they work best. You could spend more but all you will get is longevity, not better performance. Currently I have Autolites in it on a stock set-up.

 

Pretty much everybody here loves the NGK TR55's gapped between .050-.060 for NA applications. If you just want to throw a set of plugs in there and not have to worry about them for over 80K, some NGK or ACDelco Iridium plugs are more expensive than the coppers, but will last probably over 100k on a properly tuned engine. You'll want to gap iridium plugs around .040 though which is the factory spec for the trucks equipped with iridium plugs. If you have a lot of dough and spring for Denso iridium plugs, check their website for their recommended gap, as I believe that it is different than GM's spec for the Delco plug. Iridium plugs are usually pre-gapped, but it's always a good idea to check them just in case. If you have to set the gap on an iridium plug, don't pry between the electrode and ground, as this will surely snap the micro-welded iridium tip off of the plug. Use needle nose pliers or something like that to grab and adjust the ground only

 

very old post,but on that note. The factory plugs are iridium and if your engine is stock they are the best choice.