I had a 1979 Perkins-diesel F12. If I had a choice, I'd get a gas-engine one and put a 2000 in. The diesel tops out a couple thousand rpm below the gas engine, so you get effectively longer gearing with a gas engine. And of course more power if you want it.
I loved mine, but it was rusty and made very little sense to own. I did 2200 miles in it from Chicago to California, then used it to bump around it for a year, before selling. Not the easiest vehicle to own due to limited parts etc. But fun.