All is predicated on lightness.

Start with the earliest model ('79-'80) notch back, preferably one with the 6 3/4 in differential housing. Strip the car completely, insulation included, install cage with minimum tubing, 2.3 engine, 32/35 Weber carb, Cologne gear box, short exhaust pipe, no frills like Watts or Panhard, Convert the front bumper to the later one (Plastic), Plastic headlights, 13X6 Steel wheels (stock car, very light, offset to your request), Later brakes (larger), Alum rack bushings, Poly cell with electric pump.

Don't go crazy lowering the car. Only low enough for the front A arm to be parallel to the ground, or slanted down to the ball joint (preferable).

This will give a lighter than spec weight car, allowing you to actually balast the car to minimum weight.

Hope this gives you a starting point.

Incidentally, where in Ontario are you?

Bill