Ok, now I built a secondary firewall out of 1/4 ply and I spaced the engine about a half inch from it with about 2 million washers and then I cut out 24 1" squares of 1/4 ply and they will stack up to make 4 1-1/2" stand offs from the old firewall to the new one. The plane is pretty old and beat up so this was the only way to go to keep the structure strong. Hard to explain but if you looked at it you'd come to the same conclusion probably. I'll post some pics when I'm done in the next few days. The old firewall was made of 1/4" light ply it looks like and it's anchored nicely to the fuse with thick aluminum angle stock. I think it is turning out quite nicely. Only thing is at my hardware store you have to get really big bolts to get the length I need... I'll need to get some heavy 1/4-20 or 28's to make the big gap. Maybe even bigger ones lol.