On my old stroker 4inch bore hemi six initally it was tearing the flexplate apart then upgraded to a 426 hemi plate then the bolts started to come loose after every race eventulally had to weld the bolts on,i was 18 and didnt know any better.Turns out that the torque flight hemi blocks were machined with the dowel pin slightly off center and that was the cause of my bolts loosenig up every pass.Probally not your problem but thats my