Looking for a spare Slant Six near Houston

Looking for a spare engine to build up for the racecar before I pull the current one out. Craigslist doesn't turn anything up locally that satisfies the basic requirements, so I figured I'd try here in addition to the other places I've posted. Our current engine has a big ugly crack in the cooling jacket that will probably make it through the Fall MSR race, but might not be worth fixing after that.

Needs:
-Forged crank 225 slant six (pre-1976)
-Complete rebuild-able long block in good shape (no block cracks or otherwise trashed parts that are hard to replace)

Wants:
-Later forged crank 68-75 block (5 freeze plugs, casting number 2806830)
-Not previously rebored, or bored no more than .030 over and not currently needing more than a hone job
-Located anywhere near Houston, or willing to ship cheap (Fastenal/Greyhound) or work out Lemons delivery service to MSR
-A-body oil pan
-Flex plate, I guess?

Don't Cares:
-Manifolds (got what I want already)
-Accessories (ditto)
-Camshaft (probably gonna be replaced anyway)