Started to do my short header swap yesterday. Started yesterday afternoon and GOT stopped in the evening because I started to install the driver side and when I got to putting in the bolts I noticed that the upper forward most bolt hole was filled in, and I thought to myself, no freaking way. I started looking at all the stud bolts since all 4 corners of the manifold had the studs and low and behold a broken bolt. I found it odd because I soaked the bolts with pb blaster, and warmed them up and they were all coming out no problem. When I inspected the broken bolt the center is rusted not a fresh break and clean metal so that tells me that it's been open for a while. So today I get to try extract a broken bolt in my head that wasn't my fault.