Why some press photos show the manifolds red is because the engines were painted with the manifolds on but after running the engines the red would burn off revealing the actual color which is yellow. When my father took delivery of the brand new KM-2500 back in March 1, 1968 I clearly remember the exhaust s being yellow. A 1960 GMC tilt cab commercial confirms that, you can find it on youtube. I painted the exhaust manifold on my 478 yellow as well
