Complex sentence: The GM V8 was only heavier and less than longer than the Rover straight-4 and sent the GM Oldsmobile/Buick cast-aluminum "215" V8 back to the UK for evaluation.
Split into simpler sentences: The GM V8 was only heavier and less than longer than the Rover straight-4. He sent the GM Oldsmobile/Buick cast-aluminum "215" V8 back to the UK for evaluation.