I got a 454 off of ebay for $300 complete. It needed a cam and have a few bent pushrods. But, I tore it down completely. The whole bottom end was in pretty good shape. I'm just getting everything checked out, cleaned up, and machined. Of course I'll be reworking the heads, adding a better manifold, carb, disributor, etc. But, if I had to, i could use what I have and be out about $1500 total.
The main thing is to try to get something close to where you're at to avoid shipping charges. i had to drive just over an hour to pick mine up. Well worth the trip!
1972 El Camino SS 454 (original SS 350)