I wouldn't think your extra clearance on your #5 would cause a vibration. Your oil pressure should cushion that. Did your oil pressure change when the vibration start? All your bearings (even your rod bearings) looked scrubbed to some degree. I just took apart a 1976 440 that had original bearings in it. The 440 bearings looked better than any bearing in your pictures. Maybe a vibration damper failure? Lack of oil pressure? I agree with the larger clearances as well, unless your running 0W20 oil, in your non-performance engine. Just my