Those 1989-1991 Ford vans are some of the best ever made. EFI and OD trans are stout and last 200k miles when maintained. I have a 1990 Chinook on a Ford chassis weight is 10500 lbs and I get btwn 10-14 depending on terrain. 460 gas
Go to youtube and get "top gear van Sabine Schmitz" or similar and see a short low Transit diesel 6 speed manual go around nurburgring passing Porsches, Bernzs, race bikes and lots of other vehicles. Its a short van that hauls.;;
Here's the link;