I sure wish I would have read this post before installing my 408 Blue print Stroker in my 71 duster with headers. Once I got the motor in and bolted up to the mounts the Boss on the side of the block prevented me from bolting up my header to the head and I did not want to have to remove the steering linkage along with lifting the engine to remove the header enabling me to dent this area in as that would be a PITA and more time consuming so what I did was use a 2"x2" treated piece of wood about 12" in length and I positioned it on the 3rd header tube where it was hitting the boss and from underneath the car I took a BFH hitting the bottom of the 2x2 a number of times, about 12 swings and I was able to dent this area of the header in enough so that I could bolt it up to the head. I got lucky in doing this. No vibration or exhaust leak in this area. Whew !!!