How do you change a 1400 16v to 1600 16v astra?

To change a 1400 16v engine to a 1600 16v in an Astra, you'll need to replace the engine with the 1600 16v unit, ensuring compatibility with the existing mounts and transmission. Additionally, you'll need to update the engine management system and wiring harness to accommodate the new engine. It's also important to check and potentially upgrade other components like the exhaust and intake systems for optimal performance. Make sure to follow all local regulations regarding engine swaps.