Reading eBay auction listings, it's important to look at the disclaimers. Such as ...

This is a non-running experimental vehicle being sold AS-IS / WHERE-IS.

and

Proof of the "Documented 173 [Miles Per Gallon!]" has yet to be found.

and

The exact origins of this vehicle are unknown.

Experimental 1972 Honda 600 modified for fuel efficiency, from eBay

Experimental 1972 Honda 600 modified for fuel efficiency, from eBay

OK, so now that we've gotten those out of the way, what do we have here?

It's apparently a 1972 Honda 600 that was heavily modified during the 1980s to achieve ultra-high gas mileage, most likely (as the seller notes) "on a closed track under special circumstances."

It's been hidden away in a museum, the seller says, from 1995 until now, and is "in need of minor repair" and missing its ignition key. It's located in Fort Wayne, Indiana.

Remarkably, no one seems to know who built it or where the purported 173 mpg was achieved, despite periodic discussion on fuel-efficiency forums like EcoModder.com.

Experimental 1972 Honda 600 modified for fuel efficiency, from eBay

Experimental 1972 Honda 600 modified for fuel efficiency, from eBay

The technical details make it even more bizarre than it looks:

  • Wheelbase extended and (probably) original two-cylinder 600cc engine moved forward
  • Single-cylinder diesel engine fitted further back in the chassis
  • Twin fuel tanks mounted on the firewall
  • Snowmobile-style belt-drive pulley system linking the two engines
  • Aluminum and fiberglass front and rear bodywork extensions to length vehicle and achieve boat-tail shape
  • Aluminum underbody panel to smooth airflow and four removable wheel-opening skirts

The seller has put the car up for bid on eBay without a reserve price, though s/he reserves the right to end the listing at any time. It's been publicized by Bring A Trailer and other sites, and the seller has also posted a whole raft of photos outside eBay as well.

Experimental 1972 Honda 600 modified for fuel efficiency, from eBay

Experimental 1972 Honda 600 modified for fuel efficiency, from eBay

If any of our readers can contribute further information about this car--who built it, whether it achieved the 173-mpg rating, and any other history--please leave that information in the Comments below.

Meanwhile, if you're interested in the car, the auction ends slightly before 3 pm Eastern time tomorrow.

What would YOU pay for this car? And what would you do with it?

Leave us your thoughts in the Comments below.

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