Spark Plugs - brand??

[LannyL81]

Thought I would check the plugs on my newly attained LT4; found them to be the original ones, AC 41-943. Car has just over 43k on it, but it is 9 years old now.
Thought I would go ahead and replace them but would like to know what the owner's recommend. Brand and gap.

Thanks,
LannyL81
Tucson, Az

 

[stgry1]

Opinions vary. Personally I run NGK 55s. Awesome plugs and since I wll be spraying...I needed to get rid of the platnium junk. Many like Iridium and I haven't read anything negative on them except the price. Have fun putting them in! :eyerole

 

[GS977]

i just installed a set of denso iridium plugs last weekend and it runs great. seems to run smoother and more throttle responce. the only drawback was the price....13.00 per plug @ autozone.

 

[LT4BUD]

Thought I would check the plugs on my newly attained LT4; found them to be the original ones, AC 41-943. Car has just over 43k on it, but it is 9 years old now.
LannyL81
Tucson, Az

Theoretically the original should be fine....they are 100k mile plugs, BUT reality is that everyone who has ever removed these plugs has found some or all of the platinum "pucks" missing so by all means change them ASAP........

I am running Denso IT20 iridium, Denso recommends IT16 for stock, IT20 is one stage colder.

Some other good choices out there, BTW apparently GM has never fixed the puck falling off problem, so DON'T put in the original AC 41-943's

 

[jason r. nugent]

spark plugs

spark plugs are very important to the LT4 i use only the best platnum 4plus bosch there the best and available anywhere gap is pre set and no adjustment is necessary on platnum plugs if its wrong replacement is necessary

 

[LannyL81]

Installed a set of the Bosch +4 Platinum plugs. Was not really as bad as I first thought....had to remove a few things, but all in all not that bad of a job. I did drop one of the new plugs and of course it hit on the electrode. I bent one of prongs back out and used feeler gauges to get it to be about the same. And then I installed this one on #1 plug so if I have to I can easily replace it with another one.


The really good news is that my Check Engine lite did not come back on. It was only a short drive, but I am hoping....

Later,
LannyL81
Tucson, AZ