Knocking 340

Personally, if it turns over easy, and there was no known water in the oil, or oil in the water, holees in block, or parts sticking out, I would probably buy it if it was reasonably priced. Always loved the 340's! I know its hard to track down some problems, prior to dis-assembly, but a good look over and no major problems catch your eyes, Id buy it!
It takes same amount to rebuild a small block 273, 318, 340, or 360 really, as long as no big problems to start. Also, get some sort of (written) guarantee before purchase, for any concerns you may have. Saves both parties stress, after the fact...