I have two tasks - the firewall needs to fit the engine, and I have to patch the gaps and then extend onto the strakes. On the first, see the attached Word document with embedded pictures. On the second, see the following. First builder Chad planned on a Mazda engine, and I'm using the wide deck angle valve Lycoming. The Lycoming is wider, requiring a wider cowl matching to a wider fuse. I defined the fuse shape as I made the cowling, and now I need to expand the area covered by the insulation and firewall. Also, Chad skipped covering the fuel sump and the wing root / aft wall of the fuel tanks out past the wing attach bolts. I want to cover that area and, separately, add the wing root heat shields. See attached photos showing the fuse area I need to cover. I have a big sheet of stainless that I could cut, but I'm hearing about some modern products that do a better job at lighter weight. Les Laidlaw came up with a high tech product out of Italy: Teknofibra, now a subsidiary of Volkswagen. It is described as "Can manage temperatures up to 800'C only transferring through 35'C on the reverse of the panel it is mounted to." Les used FiberFrax against the composite bulkhead, then the Teknofibra, then stainless steel tool wrap. I'll follow his lead, substituting ceramic felt for the fiberfrax - it is easier to work with and has a higher heat resistance. (Commonly used for kilns and fireboxes, as it has a 2300F temperature rating. I used the same product for the heat shielding of the gear legs near the brakes.) I had a choice of SS alloys for the tool wrap (cut with shears as it is thicker than foil, too thin to rivet or weld). I went with 321, an alloy with extra corrosion resistance. The spend is $150 for Teknofibra + $60 for tool wrap + $20 for the ceramic felt = $230. The three products are shown below. The commerically available products leave me with a lot of left over foil and felt. I'll try to find another builder who can use the products.