I've owned my 88 now for five years and I have changed engines in it every year I've owned it. I have just completed my filth engine swap in it.
1st swap, Bought the truck with bad motor, I swapped in a wreaked idit
2nd the idit broke a valve guide, so I rebuilt it. this was my first diesel rebuild, asked about cylinder wall erosion at the machine shop, they told me not to worry about it. 12 miles later most my antifreeze was in the back two cylinders.
3rd swap installed a runner I had out of my 93, so that I could put the rebuilt motor in my nicer 93.
4th swap, pulled out the running motor for a rebuilt motor with an hx40 experiment.
5th swap pulled the motor to put in my 93 and put back the motor I installed the 3rd time.
Some would say I'm crazy, but I know I just stubborn and it would cost too much to start on a new truck.

 

You should have it down to a science by now.

 

I might have you beat... depending on the definition.

Technically, I only did 2 swaps: Original motor -> "refreshed" runner(that I screwed up on) -> rebuilt original motor.

However, I pulled and reinstalled the "refreshed" motor at least half a dozen times, trying to fix one problem or another. (I had a Typ4 cam that may actually be a Stage1 cam that needs to be 1 tooth off; this caused me tons of issues)

So in terms of raw pulling and reinstalling, I probably have you beat.
In terms of /successful/ swaps, you have me beat.

 

Macrobb we might have to get a vote to decide the winner. as for the science end of it. I don't have to make a lot of trips to the tool box to get the right tools

 

I believe I might be the winner here, owned my 88 7.3l 5 speed 6 years now, put 150,000 miles on it bringing the grand total to 250k...never even had the valve covers off.....