exactly...you can tell when detonation has occured by looking at the bearings. Matt mentioned the bearings were fine so that leads to say that the lean issue was not the problem. If it was his bearings would have been shot all to hell. All you would have had to do would have been pull on or two rod caps at random...check them out as well as just pull the main girdle. If there were no signs of fatigue or oil starvation or detonation then everything would have appeared to be ok. That crank i guarantee you had issues before you assembled this engine. The main problem is that it was not caught before the assembly. A visual inspection of the crank just won't cut it. You'd have to thoroughly clean the crank then do a dry mag check then a wet one or zyglow the unit to check for overall defects.
