This last fall i bought this 4 eyed 86 gt with 347 and 10,000 on the motor. It had lots of power during test drive and seemed to have good compression. It sounded great.Had high oil pressure and everything seemed pretty good on it. After i got it home and drove it for a week it and after testing out down a few strait stretches it started to smoke some. One day gave my friend a ride in it to show off and couldn't resist myself and she blew!! A valve broke off and dropped one down on my piston at about 6,500 rpm! (has a cam designed to rev that high by the way). Not sure why it broke off. The car has afr 185, and i sent the head that had the damage to get welded. I am guessing that the head had afr valves. Didn't see any valve float problems on any of the other pistons. Can valves go bad and just break off like that? Anyway my question is what are some tips to rebuild this motor and avoid problems like this happening again? I have a guy that i know that is going put the motor together for me. He is mostly a chevy guy but how do you know if people working on your motor actually know what they are doing? I don't have any race shops around where i live and this seems to be the only option. Just looking for tips on building motors so they have good reliabe power. Also last and i can feel safe opening them up every one in a while and not worrying about it going to blow up or something Input much appreciated thanks.