This is advertised as a 70 something parts bike. Asking price is $650. Only information given is that it has a racing engine...

Looks like a CT1 or a AT1MX

Based on the one picture, I'm going to guess a 70 or 71 CT-1. Left side case cover and no torque induction (reeds) set up on the intake (pre-1972), plus (less reliable) the badge bike fuel tank (pre-1972) and the top of the triple tree is black and not bare metal the way the 1969's were. I'd buy it. Lots of interchangeable parts with the 69-71 models, both CT and AT.
But talk 'em down some on the price first!

Thank you , It's not far from me so I'll go look it over.

Just talked to the guy on the phone. He's already promised to hold it until this afternoon for someone coming from further away. He said he'd call me if he doesn't buy it.

The serial number (VIN) will tel you the actual year. Someone else would know better, but is that the original cylinder and head, or is that part of the "racing engine?"