they were only made for a couple of years, the 066 superseded them in a hurry, and in truth an 046 is a better saw too.
Couple that with about 3 different versions all wearing the same 064av badge, it makes finding parts interesting.
If you plan on modding one they respond very well to it, so a lot of guys like the hot rod version, its like a more nimble 066, but you sacrifice some reliability doing so (depending on your dremel skills and how brave you are at modding) Last I checked and its been a couple of years, you can still get factory pistons and cylinders, carburetors, bearings and seals, but pretty much everything else is aftermarket or used. And a lot of the parts are just different enough to not work on the different versions, coil flywheel and exhaust being prime examples
I would seriously avoid the chinesium 064 pistons, they are poorly modified from some other saw, and often the clearances for the crank are wrong. unless you think a built in knock is a cool thing...
I'll dig around in my pile, I might have a parts saw with good tank and cases, though it may of gone away with the 064 I resurrected a couple years ago.