413 in the 68 barracuda

I have NOT read this whole thread, and my point may have already been covered, but I'm gonna comment anyway.
Your head choice WILL be guided by the pistons you can find for a 413, assuming you won't be buying a set of mega dollar custom pistons for it. You'll need to calculate compression ratio carefully, for each head you might want to use, to get a compression ratio you can live w8th.