Aircooled Mechanical Tech
I've, after taking apart my engine, found I need to replace the B+Ps and looking at VW Heritage and Machine 7 have found a few different ones.
I know Mine are 87mm for a 1641cc engine.
Anyway VWHeritage gave me a few options:
Barrel/pistons 1641cc Forged Set of 4, Mahle AC198870F...