Most H22A engine parts except for the parts in the block are compatible with the F20B.
Interchangeable parts are as follows as far as my knowledge goes:
1. Timing Belt Tensioner.
2. Timing Belt Pullies.
3. Cam Gears.
4. Camshafts.
5. Valve Springs.
6. Engine Head.
7. Intake Manifold.
8. Exhaust Manifold.
9. Intake System(Cold Air or Short Ram).
10. ECU.
11. Clutch, Flywheel, Pressure Plate and Throw Out Bearing.