When the piston diameter is larger than the distance it travels in the bore it's considered a "short stroke" engine. Our 4.0L have:
bore = 3.95
stroke = 3.32
There are certian traits of long stroke and short stroke motors.
Short stroke motors have slower moving pistons and thus require less timing. And for the sake of this post they move less air for a given rpm of the crank.
They develop thier peak TQ higher in rpms... which brings up a point. Actually a short stroke motor in a truck is backwards. A truck is generally used in low rpm ways. It woud make more sense to have a long stroke. That way you get more low end TQ in a engine that's most likely never going to see over 5000 rpms. But this motor is a eveloution of the old german V6 from the 70s.
Over time the motor has been stroked and bored to increase it's size. And as such you can only go so far before you run out of metal and it's integrity / shape.