Assuming the same type truck and tire size, what actually makes a 4wd truck taller than the 2wd trucks? Are there more leaves in the back on a 4wd, and are the coils just taller? Are the shocks different as well? How much taller are the 4x4 trucks over the 2wd trucks?

If I wanted my 1989 F150 standard cab 302 2wd truck to sit as tall as a stock 4wd truck, what exactly do I need to make that happen?

 

a body lift would be your easiest/cheapest way. you'd basically otherwise need a lift kit, and ya misewell go buy a 4x4 truck before ya did all that.

 

I've seen all different heights. I own a 97 F250 HD 2wd. Everyone thinks my truck is a 4wd. I've seen some 4wd that look 2wd. Just go with a 2" lift and you will probably get the look you want

 

just remember,the lower they sit,the better fuel economy they can get, due to less flow traveling over the "dirty under garage".
this is the main reason 2wd's get better economy than 4wds.it's not so much due to the extra weight of the front axle and t-case,but less air low due to sitting lower.
consider enjoying your advantage.

 

I converted my 88 F150 2wd to a 4x4 by using a 89 F150 4x4 as a donor.

The 4x4 rear uses a 2 inch lift block. It also uses as you said
a leaf spring which has a couple of more leafs. The 4x4 spring is 3 inches
wide and the 2wd spring is 2.5 inches wide. I don't know how much
lift the 4x4 spring causes.

I kept the 2wd leaf springs.

For the front, the coil springs for the 4x4 measured 2 inches taller than the
2wd springs.

My truck sits level with no load in the bed.

On the 2wd I originally had 235 75 15 inch tires.
I installed 31 10.5 15 inch tires.