No specs on the air conditioning?
That clear bubble on a nice summer day, has to be over a ton of AC.
With only 8 horse max (shaft?), somewhat less at the wheels, 1 ton would eat one of your ponys!
A SWAG estimate, the highway 235 would drop by half with the AC on max.
Even if it drops by half, that's still 120 MPG (gas) and 140 MPG (diesel).
Yeh, performance would suck, but so what.