I had the same issue. I ended up going with J&C Enterprises (ebay store)
. They have 2 separate 0331 head's. I called up and spoke with them before ordering.
The $319 one may
be the TUPY head, but they won't check before hand, and it's possible you'll get the weaker one. It's kind of a gamble for $100. LINK
$419 on may not be TUPY per se, but they are definitely the thicker, better casting (obvious to see around the head bolt holes). LINK
Free shipping, plus they include a return label for the core. One thing to note is that mine did not come with the manifold alignment dowels, you're going to want to check before sending it back, and pull the old ones out.
There were about 3 or 4 different casting throw offs in the head, where the thermostat hooks up. It's a pain in the a$$ flipping that thing around, but if you can, make sure that you do and get everything out of there. I ended up missing one, and the first time I started her up, I damn near ***** my pants from all the noise, and wound up taking the head off...again.