My kinder surprise was an overly shaved head that was way too high comp and some rough machining on the deck...machinist took forever to get around to it. Not at all saying my man hasn't sidelined his engine builds for drive in drive out mechanical type work, but that's been a major hold up for us. Talk is end of the year for completion so fingers crossed.
But yeah luck of the draw with second hand engines. Have to ask yourself; there's usually a reason the engine is for sale - either the car got thrashed out and trying to offload problems, a part out (why?) or stacked, in which case strong possibility of a hard life pre-stack too. Lot of shit engines out there. My seller didn't lie about having issues with the engine before I bought it - it was worth more in parts than what I paid for it, which is why I took the risk. On the bright side I got a chance to make it powerful and near bulletproof.