As one would expect, the 5-ish year old parts-store brand plug wires in the Chevelle didn’t cope very well with the headers; I knew they needed replaced but they’re worse than I thought. Fortunately I’ve got a nice set of Taylor 8mm silicone-jacketed ones going on which should actually survive the heat.

Relatedly, I’ve got those woven boot protector socks/sleeves and I’m pretty impressed. While there was some minor burning under them, it wasn’t nearly as bad, and I even had one wire which wedged itself (in the sleeve) firmly against the primary tube and showed no sign of burning.