Spark Plugs

[pontiac6ksteawd]

Not sure if I have this in the right section or not, but here goes my problem.

I bought some plugs off another member who thought they were the older #8 rapid fires. Turns out they werent. They are R42LTSM. Now I know the TGP takes the R42LTS, and the 6000 takes a R44LTSM. What is going to be the diference here inbetween these if anyone can tell me?

Trying to do a tune up on both cars..

[TGP Nick]

Yep- wrong section.  Should be in Performance or General.

[mfewtrail]

Brian, the "M" stands for "Special Design Electrode" design according to AC Delcos website. My 3.4 DOHC crate engine has those R42LTSM's in it. I would probably just buy a set of R42LTS plugs or the Autolite eqivalent(# 103's, the standard ones are about $1.50/each at parts stores and they can be had at most Walmarts for $1/each.)