So I was thinking about pulling the trigger on buying a 91 350sdl. 228 thousand miles, seems to be well maintained, good carfax report. Asking price 5000. What are the pros and cons of this vehicle. I understand the 3.5 liter is prone to problems and not as reliable as previous 300 series diesels, but is this enough of a reason to not pick one up? Are they still decent for a vegetable oil conversion? What does a typical engine overhaul cost on these? I am currently waiting on a mechanic's inspection. Good purchase or no?