Complex sentence: The standard 6.6L (400 cid) V8 engine got a slight detuning for better fuel economy, while the 7.5L V8 soldiered on for one more year.
Split into simpler sentences: The standard 6.6L (400 cid) V8 engine got a slight detuning for better fuel economy. The 7.5L V8 soldiered on for one more year.