It looks just like the other three groove small block pulleys that I had from the time period of mid to late 70`s. No welding that I can tell. E58 was police and certain performance models. I was wondering if somehow it was balanced as part of the engine assembly or not, as when I removed it I didn`t realize it had the drilled holes as it was covered in muck. Another odd part was that one bolt was longer then the rest. Not sure why. It doesn`t have offset holes.