They are. The have
oil in them with a dip stick and then the belt. Very low boost as most of them are around 6 PSI. I had one on a 351W in a superformance back in 2000 and had to put a bigger disc inside to handle the needs of the bigger 351 and it pushed around 10-12 PSI. I have some pics in my gallery. Paradise Wheels in Ca sells Paxtons and parts for them.