Prepping Firewall Forward

So glad to be done on the canopy! I installed all the seals, and everything seems to work fine. Won't really know until I encounter some rain. It's one of the hardest parts of the build and I'm pleased with how it turned out. Now moving on to firewall forward stuff. Because I'm using the IO-390-EXP119 engine there's some differences that need to be addressed from a standard IO-390 install. Normally you'd build in these differences per plans as you go. Mine is a QB fuselage that was built prior to the -EXP119 version being approved so these alterations must be done on the now completed fuselage. I first needed to modify the 2 lower cowl attach plates already riveted on the lower firewall. This is to accommodate the different exhaust system. The 2 options were to drill out the 16 rivets holding them on, make the modifications and rivet them back on. The other options was to trim them while still attached. I elected to do the latter since access was wide open and I thought it would be quicker. I figured if I messed up the trimming I could still drill out the rivets and make the needed modifications that way. In the end I marked the material that needed to be removed and using a combo of Dremel tool, oscillating tool for sanding and multiple files I got the needed material removed and a good result. I also needed to cut an additional hole in the stainless firewall for an engine control cable pass-through grommet. Using a template to position it and a 1/1/8" step drill on low speed and with lots of oil got it done. Stainless is tough stuff to drill. High drill speeds create heat that work hardens the metal making it even tougher.