I couldnt see the photos,but I know what you are describing--I had a 454 with the same symptoms--it turned out to be bad cam lobes and lifters with concave bottoms making the rocker arm slide sideways as it hit the valve sten,even with giude plates(which were all hogged out too).The valve sten was worn some,but being cheap and broke as usual I filed it square,put in a new cam and lifters,and sold the motor for 400 bucks a few weeks later when I heard wrist pins or pistons making noises--- /forums/images/graemlins/angryfire.gif--it should have had a valve job at least,or better yet a complete rebuild. /forums/images/graemlins/crazy.gif