Best Vortec head spark plugs for reliability and performance?

[Dravec]

AC hasn't made spark plugs in decades. Far as I know, they're bought-in from NGK. At least, some part numbers are NGKs with different markings, in an ACDelco box. I like NGK.

I was big on Autolites until they moved production to China.

My Trailblazer came with Iridium plugs. The originals lasted 160K miles, coming out at 90K--and they looked so perfect they went right back in, even though I'd already purchased a new set. I wouldn't put Iridium or Platinum plugs in a carbureted engine, or even a TBI. But for a port-injected OBD2 engine that doesn't have a history of oil consumption...sure.

Haven't bought a Champion plug in decades; I swore I'd never buy another Champion when I figured-out they had the most-brittle porcelain in the industry. Soft, fast-wearing electrodes, too.

Not real big on "gimmick" plugs, either. Splitfire, E3, the Bosch plugs with two or four ground electrodes...No, thank you.

I tried the stupid Bosch +4 plugs in my '99 K3500 with a 454. Lost 3 mpg almost instantly. The mismatched copper/platinum mismash of plugs ran better.

 

[Caman96]

The OE Acdelco’s are on sale at RockAuto. They were so cheap I bought 2 sets. With RA 5% Off, combined shipping for 2 sets and Acdelco rebate of $8.00, I basically got 2nd set for free.

 

[PlayingWithTBI]

AC hasn't made spark plugs in decades. Far as I know, they're bought-in from NGK. At least, some part numbers are NGKs with different markings, in an ACDelco box. I like NGK.

FWIU the higher the number on ACDelco plugs, the hotter they are. NGKs are the opposite.

 

[Schurkey]

FWIU the higher the number on ACDelco plugs, the hotter they are. NGKs are the opposite.

True, along with a heap of other information, for AC's older part-numbering system.

ACs "newer" numbering system is totally random to prevent people from playing with the heat range specified for their vehicle.

"R45TS" denotes the resistor (R), the thread size 14mm, (4) the heat range, (5) the seat, tapered (T) and the extended-tip (S)

"41-103" denotes a spark plug (41).

 

[PlayingWithTBI]

"R45TS" denotes the resistor (R), the thread size 14mm, (4) the heat range, (5) the seat, tapered (T) and the extended-tip (S)

I thought in R45LTS "L" was for long reach (3/4"), "TS" was for Taper Seat for Vortec while R45TS was standard 5/8" Taper Seat for TBI. But I may be wrong - it won't be the 1st time.

 

[HotWheelsBurban]

True, along with a heap of other information, for AC's older part-numbering system.

ACs "newer" numbering system is totally random to prevent people from playing with the heat range specified for their vehicle.

"R45TS" denotes the resistor (R), the thread size 14mm, (4) the heat range, (5) the seat, tapered (T) and the extended-tip (S)

"41-103" denotes a spark plug (41).

So what does "41-993" denote other than "spark plug, iridium"?

 

[Schurkey]

I thought in R45LTS "L" was for long reach (3/4"), "TS" was for Taper Seat for Vortec while R45TS was standard 5/8" Taper Seat for TBI. But I may be wrong - it won't be the 1st time.

The letters after the heat range can be difficult to decipher. You may be right.

Just about have to look at the catalog, AND have the plug in your hand for examination to be sure.

The point is, the OLD number system has heaps of information if you know how to decode it. The NEW number system does not. On purpose. Because it's double-top-secret.

So what does "41-993" denote other than "spark plug, iridium"?

I don't think the number even includes an "iridium" qualification. Far as I know, "41" denotes "spark plug", and that's the end of the useful description.

Edit--see below for meaning of the "900-series" plugs.

 

[Caman96]

Also, according to RockAuto and Acdelco.com the number is R44LTS6, and not R45LTS. Unless that’s just an older number.
Just noticed on Acdelco site they are manufactured in China kinda wish I got the Japan/US manufactured NGK’s.

 

[Schurkey]

This isn't the chart I was looking for, but it's what I could find.

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So the 41-100 series is Iridium, the 900 series like HotWheelsBurban asked about are "double Platinum", not Iridium.

Also, according to RockAuto and Acdelco.com the number is R44LTS6, and not R45LTS. Unless that’s just an older number.
Just noticed on Acdelco site they are manufactured in China kinda wish I got the Japan/US manufactured NGK’s.

The final "6" means .060 gap, via longer ground electrode.

Chinese? Marvelous.

 

[Caman96]

This isn't the chart I was looking for, but it's what I could find.

You must be registered for see images attach

The final "6" means .060 gap, via longer ground electrode.

Chinese? Marvelous.

More the R44 vs R45.