Well it's been years since i changed my plugs so pulled one out to see what i had in there(Want to drop it down a heat range). Well i had 3924 Autolites, After some searching i noticed that both 5.2/5.9 list two different plugs. Seems from what the Autolite web site lists pre 1997 used the 3924 and after that they changed to the 5224. 97 was the transition year since the 5.9 still lists the 3924 and the 5.2 lists the 5224. These are identical plugs(copper, same heat range) only difference is the 3924 is gaped at .035 where the 5224 is .040 Not sure if anyone else noticed this just wondering why they changed over to the .040 gap plugs?

 

good question and something I always wondered myself, when going down the rabbit hole reading about 2nd gens before. I know the first few years of the 2nd gens, I think only 1994 and my truck's year 1995 used EGR valves then totally eliminated them. I very vaguely remember reading the obd2 rams had a little better HP. Maybe some type of tuning that was done with the obd2 computers mixed with not having EGR anymore.