I'm looking to get new sparkplugs for my car.
I have ac delco R44LTSM's I want to get plugs with a short thick electrode, perhaps a colder range and that will still work in my vortec heads.

I'm going to be using nitrous soon.

 

the letters have to do with the thread size, reach, tapered or gasket, and i believe overall length. the numbers are the heat range. check the web site of whoevers plug you want to run for me detailed info.

 

Right, each mfr has a different set of codes...

The AC ones are fairly simple. 1st letter R = resistor; 1st number = thread size (4 = 14mm, nearly all auto plugs are this size); 2nd number = heat range: higher # = hotter; L = long reach; T = tapered seat, no T = washer seat; S = extended nose (ceramic & center electrode protrude 1/16" or so past the shell), no S = standard nose, where the end of the ceramic is even with the shell; no idea what M is.

Other mfrs' schemes are similar but not identical. One step in heat range is a different amount from one to another. For instance, a 3 # step in Champion is about equal to a 2 # step in AC. Other than the heat range, they all have to have the same sort of variations in construction; some (Champion for example) include construction details like C = copper electrode.

 

thats what I was lookin for, thanks guys :rockon: