Glowing Exhaust Manifolds 1992 454 TBI 7.4L P30 Motorhome

[Fast355]

I tripped over one at the junkyard today. I've seen a lot of this type on motor homes. I can only assume GM used these because iron cracks too easy at high temperatures.

Holding closed loop at higher loading can cause the manifolds to glow as well. This is what my coated stainless headers on my Express already look like. The coating is discolored, chalky looking, almost looks like it was torched with an acytelene torch. I am thinking it gets quite hot pushing a brick into the wind at 80-90 mph especially into a 20-30 mph headwind. Those are LT1 90* metal plug boot shields designed to reflect heat off the plug wires.