1979 Ford Econoline
The seller of this jet-powered Econoline has it right – there certainly is the potential to make money with this beast at various air shows and drag race events. 300mph in any sort of land-based vehicle has to be terrifying, though, so the market for this sort of thing has to be severely limited.
Sadly, the seller has posted no photos of the interior, which is said to be filled with chrome-moly tubing in a sturdy cage. Get that thoroughly inspected before you take your first high-speed run, and learn to pack your own parachute.
It’s on eBay in Alabama for $40k or offer.