Unimog 421 Restoration (Part 11): OM616 Cylinder Head overhaul, but will it run?

This is part 11 of a series looking at the full restoration of a Unimog 421. The engine has been a non-runner for many years, so in this episode we look at the removal and overhaul of the cylinder head to try and bring this little Mog back to life! Previous episodes of this restoration series can be found here: Part 1:    • Another Unimog 421 restoration begins! (in...   Part 2:    • Heat, hammers and rot! Unimog 421 restorat...   Part 3:    • Will the engine need an overhaul? Unimog 4...   Part 4:    • Unimog 421 restoration (part 4): complete ...   Part 5:    • Rebuilding a classic Unimog’s rotten cab f...   Part 6:    • Unimog 421 restoration, part 6: Fixing the...   Part 7:    • Unimog 421 restoration part 7: Painting th...   Part 8:    • Unimog 421 restoration part 8: axles, brak...   Part 9:    • Unimog 421 Restoration Part 9: Thrust Tube...   Part 10:    • Unimog 421 restoration part 10: Wheels on ...