I haven't heard of anybody trying them in a 3800, but the OEM Delco double platinum clad 100k mile GXP plugs would fit . Right?

3500/3900...any engine after 06 really. I know my 5.3L Vortec and LS4 both had them.

So, at the end of the third page and the beginning of the fourth page of a huge thread on which spark plugs to buy, we've come to junkyards for our solution!

I like to pay $7 for my new spark plug sets. One time, PRJ Performance tried to tune with Speedway 92 octane gas, and we had erratic readings with knock every once in a while. I switched to 93 octane Marathon gas, and the readings calmed down. We were able to squeeze out a few more degrees of timing, too. Same spark plugs both times!

I think i am sticking with plain Ol' Autolite Coppers.. Ive heard u dont see much change with expensive plugs and some even, because the low compression of the N/A 3800, to run worse.. Danthurs recommends Autolite Coppers and I trust his judgement.. and cheapish ACDelco wire.

Congrats! Good decisions. I'm sure you're going to enjoy putting the money you've saved into whatever else may come up. Perhaps the Big 3 upgrade? It'* only a little, but every little bit helps!

I agree... ive been putting more time and money into audio than maintenance and that is not good.. I think i have had my fill of car audio.. and i am satisfied. Now i gotta replace plugs, wires, fuel filter and a good ole tune up. and change the tranny fluid and a tranny filter.. Is there a drain plug and dip stick on the 4t60 tranny... I know thats sad to ask. But i cant recall.. im beyond tired

There is a dip stick, but there'* no drain plug. You've got to take off the trans pan, but it needs to be done to get to the filter anyway. How many miles are on your car, and how many since the last trans service?

I bought the car with 133,000 mile and now has i little over 136,000.. and i havent messed with the trans sense i got it

That'* not bad at all! Hardly an oil change! Now get in there and preventatively maintain that "whip!"

Anyone try E3 plugs,I have them in my Chevelle.