Sources for pre-09 5.7 long blocks / cores?

I found ATK and places on eBay selling reconditioned long blocks, but the price seemed kind of high to me.

If I was in your shoes, I would find it hard not to plan for some upgrades. So I would be looking for a cheap cast off 5.7 to re-ring but with a 6.1 forged crank and a set of forged drop in pistons and rods from MMX. Provided the cylinder bores look good and the block is solid, the rest doesn't matter and would get tossed so condition becomes less important. You could even look for one that had a valve seat drop provided the cylinder didn't get scored. And I would use the Eagle pistons so I could run the Eagle heads without having to run thick head gaskets.

At the least, I would look for a cheap cast off motor and re-ring and bearing it. Cost would be lower and could probably be done in a weekend.

Or find a 6.1 and put that in.

I guess the Eagle heads would make the ModMan intake an issue though. So maybe a the 6.1 and/or Eagle heads are out, but the rest works.