Your truck and EVERYTHING else with a battery is DC powered, you won't get any spikes with DC.....You are wasting your time and money. you MIGHT get a slight voltage drop when turning on large powered accessories but within milleseconds the voltage regulator will up the output of the alternator and you will be back to normal power.

On edit I see Dixie replied better then me...That's what I get for not reading all of the posts....

Diesel Rod