[Christ]

I don't see a 400 lb weight savings from reducing ICE size. The engine itself probably doesn't weigh that much now.

Honda's 1.5 and 1.6 liter engines only weigh about 200, I can pick them up and carry them around. Hell, even the Iron Duke only weighed in slightly above 400, IIRC, and it was a 2.5 liter hunk of... well... Iron.

Remove half the cylinders from the engine, make it a .7 liter 2 cylinder, and where it could make 100 HP before, it will only make about 40 HP now. You lose torque in a non-linear scale when you lose cylinders. But you don't lose half the weight from the engine. Downscaling the cooling system proportionally would help there, but again, those components just don't weigh that much. There is only ever about 20 lbs of coolant in a standard cooling system, maybe 30.

I can see losing 400 lbs from the whole car, maybe. From the ICE and drive components, not so much.