Buying cheap used Ram V10 2500 pickups and converting them to Cummins
would seem like a good home business for someone to do
especially if the schools in your area had Cummins 12V equipped buses
that are being retired.
Some school districts around the USA have retired still serviceable Cummins
buses because of parents complaining that diesel soot is a health danger to
young children.
The 47 series automatic transmissions need to be upgraded to
higher standard internal parts like you can get from
www.dieseltrans.com
The NV4500 manuals need to be upgraded to NV5600
six speeds.
The front suspensions need mods like Lukes Link, Solid Steel braces, etc