Yeah............I do buy quite a bit of stuff on ebay, but on the engine thing it would take a lot more investigation of a supplier to get my money. They all sound good............but the people who did business with Madoff thought he sounded good too. Verify, verify, verify. One source for SBC crates who does have a strong reputation is; Crate Engines, Bare Blocks and Long Blocks

There are likely others, but that's a start.