What exactly is the "magnum engine"? And do all trucks have them? I have a 96 Laramie slt 4x4 and did not notice the magnum emblem on my body.

 

Yes,they do,unless it's diesel powered.

 

magnum is the redesigned, fuel injected version of the 318/360. around 1992 or so.
the bottom end is the same as the LA 318/360 from the 60's.
the top end - heads and intake are very different.

here's a starter course.
http://en.wikipedia.org/wiki/Chrysler_LA_engine