306 short block

Hmmm, the free shipping is nice, but that sounds very similar to another engine remanufacturer here in Dallas, and the prices are waaay better than the ebay price.

http://www.citymotorsupply.com/
This isn't including shipping of course, but they list a 5.0 short block for $305. The core charge is $135, so it'd be $440 with no core trade in. Of course, you get what you pay for. These are budget engines, built in mass, not lovingly prepared by the local machine shop.