66-73 stock small block heads?????

If you think the 340 was sweet, wait til you build a 360!
But I have to agree, 2 more gears would have been nice. Bring them all together a bit, and a deep o/d.

As to the matrix, most of it is already in your head, at least the stuff that matters.

I doubt you would be happy with a NA 273. Of any output.

A large bore stroker though?!Yeah, that'll fly.Just dont choke it with a too-small head.

If I had money, I'd build a turbo SBM. A small SBM, with a long stroke.