If you are near the Sacramento area there is always the auto dismantlers in Rancho Cordova. The Chevy/ GM dismantler is always posting complete drop out setups on craigslist. I found my motor on craigslist ($800 including wiring harness and accesories) and my transmission ($300 including torque converter).
I have about $4,000.00 into my entire swap with upgrades and made a reliable and streetable 333 rwhp.