I agree with Tech – The last set of cast iron Vortec heads I bought at a wrecking yard had several cracks on both heads that were not apparent from the outside with the naked eye. The heads were very clean and I thought they’d be fine; however, the machinist I use tells me that finding cracks in Vortec heads is pretty common especially in the area under the exhaust valve. Fortunately the yard I bought them from is local and managed by a good man and we agreed up front that I would end up with two heads that would magniflux and show crack-free. I actually took four more heads and ended up with three good ones and one more zinger. So out of a total of six heads, three were good, two cracked beyond repair and one was “fixable” but the wrecking yard manager thanked me and chucked it in the scrap heap to go along with the other recycled iron. This yard only charges $50 per head and because it cost me a bunch of time, I wrangled a tilt column from a 1971 Chevy pickup (no key – column shift for another project I was working on) out of the deal as well. I always pay these guys in cash and try to be reasonable in my expectations.

I see the lads at Phoenix Automotive are selling guaranteed re-manufactured Vortec heads for $500 a pair. These look pretty decent and this is a good price for a ready to bolt on high performance head.
Chevy 5.7 Liter Vortec Cylinder Heads (PAIR)

Sounds like you got quite the ride your workin' on! Would be great to see some pictures of this one.

Let us know how you decide.
Glenn