there was already a notch by a previous owner there to clear an old exhaust system, the muffler guy just added to it! In a big way!
Anyway it is good I did this because I also found a exhaust manifold gasket under the headers which I specifically didn't install because Sanderson's is quite specific about this is their instructions instead you are suppose to install the header with a 1/8"-1/4" bead of black RTV silicone. I looked on the drivers side and yup no gasket, so I'm guessing when Kelley chopped the frame he must of had to take header off and then just automatically put a gasket on not knowing sanderson's thing. So after cleaning off both surfaces I got a new bead of rtv on and let it set 24 hours per instructions, which allowed me to paint por-15 over the exposed metal on the frame.Also time to remember I need to add washers or spacers to the engine mounts to get read of the free space between the sides of the mount where the thru bolt goes. I also decided to make a build binder with all the loose papers, amd part numbers for anything not stock for reference down the line vs. loose piles everywhere!