Yes the vert is way lighter than the Dakota. I thought about going with the leaning tower of power and the Aluminum 833 OD tranny. Lots of parts available for them .It would be the easiest but would be less unike. My 273 used to get 17 mpg with 323 posi 8 to 1 compression and the 4bbl cam and 383 AFB on the 273 4bbl manifold with a 727 Automatic and headers.
I'm thinking that If I could get up in the high twenties I would have something. Adding FI to the 273 would help and the OD tranny as well but I dont think I can get that much out of the V8. Any one have MPG figures on the new Hemi's. Of course all those cars and trucks are way heavy also.