I don't know how you come to this conclusion, but the engine block in a modern passenger car is definitely not the heaviest part. The engine block itself is oft

I don't know how you come to this conclusion, but the engine block in a modern passenger car is definitely not the heaviest part. The engine block itself is often incredibly light, even a V8 made from cast iron would only be a few hundred pounds. The body (or unibody) of any modern car is far heavier, given that it has so many functions and safety features as part of its design.