Cam design limitations

This is how I understand it... It's not about the exhaust gases expanding as they exit. Because it doesnt. As soon as that the flame front goes out, the gasses begin to cool, the more distance they travel, and more surface area they touch, the cooler they get. As an example... At the exh valve, they are around 1200°. At the port opening this drops to 900ish. After the first turn in the header, 800, at the collector, 400. As they cool, they slow down and contract. You wrap headers or coat them to keep that thermal drop to a minimum over the length of the pipe. If the energy that is lost by thermal dissipation is retained, that energy goes directly into the turbo and produces boost faster. My impression is, if that coated tubing is wrapped, it will result in fractures in the metal. I've seen that on motorhomes with stainless manifolding too, never mind plain steel.

Bill - If it was me, and a serious effort, I would not be using anything you are...lol. I've be making my own exh manifold/turbo mount, and having someone weld up a sheet metal intake with a large raised plenum and centered throttle body. It would not be carbureted. It's too easy to grab a junkyard EFI system and retrofit or by something like Megasquirt. I got spoiled when I ran a ProCharger dealer years ago. Carbureted boost is like replacing a 5.0L in a Fox body with a flathead V8 with Offy heads and intake, and Strombergs. Sure, it looks cool and does make some power. But you're leaving a lot on the table. Tunable EFI is the way to get intercooled turbo cars to run hard consistently.