The $1,600 mistake I made at the Pomona swap meet taught me to bring a magnet
Two years back I bought what looked like a clean set of small block heads at the Pomona swap meet, paid $400 cash, and felt pretty good about it. Got them home and a guy I know pointed out the casting numbers didn't match what the seller told me, plus one of them had a hairline crack near a bolt hole. I ate the $400 but that whole deal made me start carrying a magnet and a flashlight in my truck to every swap meet now. Last month I passed on a "fresh rebuilt" alternator at a yard sale in Riverside because the magnet stuck to the housing where it shouldn't. Curious what checks you all do before handing over cash at a swap meet.
Did you ever hear about that trick where you tap the parts together and listen for a dull thud instead of a ring? A old timer at a garage sale told me that one. Saved me from a cracked manifold last summer. Cracked metal sounds dead, good metal rings out. I do that plus the magnet and a small light now. Takes ten seconds and it has paid for itself already.
Man, the tap test is solid but have you ever asked the seller to let you clean the part first? A dishonest seller will get weird about it fast, and that alone tells you plenty.