if you fit 2.0 8v bottom end you can keep EVERYTHING literally just need to bolt on servicable MK2 head and thats it.
although, being a tall block there is a chance the 4 branch will hit the tunnel, so mgiht be in your interest to go with a 1.8. can get em for cheap if you're patient, and fyi carby 1.8 blocks are the same and MK1/rocco/MK2/early passat will all fit.
MK3 is a slightly different unit, you can tell as it has the breather on the front. Some passat blocks were lower compression too iirc, so if you do get a passat lump make sure its PB code like yours