If the old plugs are just that... old, worn out, and barely firing the cylinder, simply replacing the plugs with ANY new one would get you BACK a bunch of power.

 

I didnt.... thats why I asked for clarification

 

tires have a lot to do with it. My 1996 5.2 with a mopar PCM and 33 inch BFG AT KOs would spin on pavement easily with the 3.55s (it was annoying).

Old tires where the rubber has hardened makes it easier.

Also, trucks are much lighter in the rear than other automobiles. Hence making it easy to spin the tires.