I bought 4 pair from Lee Millers auto. He bought several pallets of engines and parts from Ray Evernham when he went to GM in Nascar. Lee raced Nascar truck series. He still has tons of parts on shelves including complete race engines with W9 top ends. I took a bunch of W5 and W2 top ends out to Ryan Johnson at Shady Dell . He screwed me on everything. X blocks , Batten Heads, Everything disappeared.
Lee Miller still has more Parts then you can imagine. He says he don't but I been in the upstairs of the shop. I found the only W5's that are worth anything are some with blue pipe plugs. All other have bad porosity problems and don't hold seats or guides the aluminum starts flaking away. Indy 360-1 rectangle CNC port heads Make more power then others for less money . Unless you can find a set of the first W2 rectangle port Batten heads designed by Oldsmobile. But then get ready to put tons of money in them.
There is another shop in Lansdale with a stash of 64 Max Wedge top ends. But then that **** is out dated now compared to some of the later aluminum heads. The old **** is great to look at but gathering all the parts to use them is crazy. And when you break something your on a year long hunt for parts.