SonexBuilders.net

Area 51% wrote:An old junk VW head makes a wonderful fixture.
They are everywhere.

What specs would I need (year, bore, etc) to get an old head with the right dimensions? That’s a great idea.

The dimensions are the same on all the Type 1 dual ported heads. Anything 1972 or later will fit the bill. The bore doesn't matter.

If you can't find anything cheap locally, I have an ex-Aerovee head that suffered unscheduled valve seat removal you can have for the cost of shipping. UPS thinks very highly of their services lately.