randy harris,the 55 m.p.h you mentioned seems to be a significant number when discussing 'scuttle shake' most people say it accures at just about that same speed as did mine,in a effort to correct this problem on my 63-bj7 i stripped the suspention to the bone, front and rear replaced/rebuilt the entire front end and rear, everything all susp.components.i can best discribe my 55 m.p.h. shake as the 'whoocheekoochy' ya it was pretty bad,all the work shifted the frequency to about 72m.p.h and very much less of a shake,with no noticable jumping around when traversing pot holes or r.r. crossings,what seemed to totally erradicate the problem was when i purchased a new set of all four and the spare with very well ballanced'dayton' chrome wire wheels and new radial tires,it totaly changed the driving experiance,ive had the car up to 110 m.p.h.and the car tracked very well felt very stable and tight demonstrating the requirement of a good set of wheels and sneeks on these cars,im not suggjesting everyone needs new chrome wire wheels,just that a good clean straight set of wires and new well ballanced tires makes all the diff.in the world,and i dont recommend everyone needs to test this by driving at 110 m.p.h perhaps i wouldnt have done so if i was sober.no just kidding,that run was done on a private airport runway in penn.