What are the best spark plugs to use in my 3.4.

 

AC delco, basically the spark plug that came with it is best for it until you start making LOTS of horsepower or are using nitrous, s/c... Stuff like that. I dont know the exact part # but I know z28pete has posted it up before, search and Im sure youll find it.

 

delcos are good, i put in a set of autolyte plats. they're my fav for my cars

 

AC Delcos are the best, plase no bosh(they tend to not be nice in our cars)

 

Like champions, they work great in my lawn mower

 

It'd be best to stick with your conventional nickel chrome alloy AC Delco plug part # R43TSK. Or if you want to kick it up a notch you can go with AC Delco Platinum 41-803 or iridium 41-101. NGK and Denso are other good brands for spark plugs if you want to try something different than Delco.