Had a hot 2.1 in a kit years ago. High compression and ported head and lightened. Running on twin 45 webers and tuned by Tom Airey, it made 165hp at the wheels, and cruised on the motorway getting 30+mpg, pushing a longish Mk1 Granny back end.
A better engine option would be a Zetec, running on an early ecu and ignition. More power and lighter, and Type 9 bolt pattern.
9" Ford with a pInto would not be a weight saving option, but does give the option of many gear ratios. The Sierra Cosworth 9" diff came from a yank production car, can't remember which though.