I decided to replace the bottom firewall fasteners with Skybolt 1/4 turn fasteners. This meant I needed to remove the mounting flanges that were riveted on earlier in the firewall attach section. Once they are removed, the Skybolt flanges can be clamped into place and match drilled with the existing dimpled holes. Once the flanges are match drilled, countersinks are drilled and then I powder coated them. The only issue is that there is very little room to reattach them with the bottom of the engine mount in the way. Looks like I will need to use some countersink Cherry pull rivets as the only solution. Preplanning would have mae it easy to rivet prior to the engine mount being installed. Once the flanges are clecoed into place you can reach inside the cowling to mark the position to drill for the 1/4 turn and sleeve.
