Took me 2+ years to get the courage to do the swap and honestly these IDI's are probably one of the simplest motors to work on. I very much prefer working on my 7.3 idi over my grandpa's 1983 mercury zephyr with carb inline 6....plus in a real apocalypse situation (that probably never would happen) you could run pretty much anything in these old diesels and they'll continue to chug along. My truck came to me with both tanks filled with a mixture of oils....fuel was black and I at first thought my tanks was dirty but after using all that fuel it's nice clean diesel nowI hope to get there with that attitude. My '85 Benz with the M110 straight six (gas) sounds like a sewing machine and I absolutely love it. Especially in the high revs.
This is my 1st diesel and I didn't know about the low top speed and noise before I bought it.
My backup plan for this truck is to change the engine to gas (blasphemy here, I know) but I'm gonna stick with it for a while because my goal was to have a mechanically-simple truck with no computer or emissions crap.