Engines that are 100% mechanical for reliability. No computer, electronic sensors, and so on. I'd get another set of Detroits with a full rebuild, but not a 6v or a 92 anything.
Cummins factory reman C series are the way to go. That’s what I repowered my 53 hatt with. Cheaper than new engines yet factory reman with all new parts and a factory warranty The price difference between rebuilding the DDs and the Cummins made it a no brainer. You also get new ZF gears. In my case I saved over 3000 pounds from the 8V71s. I was able to keep the same size shafts... only extra cost is making new engine beds. Where are you located? If SoFl or Carib check with Mavex in Miami. They re the Cummins dealer and know their stuff