408 stroker header size

Hi so ended up going with the Doug's as I can get them locally here. What a pain installing them it's all installed now glad I had the motor pulled to fit them I havent tried putting the starter in yet. it has about 1/16th of a inch between the header tube and the power steering box. Is that normal I don' want vibrations when it' all back together running. Should I shim the motor mounts up or dent the pipe up which I don' want to do.