I ordered a custom bucking bar from the Yard Store to rivet the remaining firewall rivets that are too close to the engine mount. Despite looking promising on the website, it was still too big to fit between the firewall flange and engine mount. I marked the material that looked like it needed to be removed and machined it off in the vertical mill (sorry, no pictures).
Here’s the modified bucking bar. I’ll know soon enough if it will work.
