My fuel mixtures are fine mate (I mapped my own engine), thanks for the concern mate As stated above; a lean mixture would cause an increase in Exh gas temp, also overly retarded ignition timing would have the same effect too.

Realistically id say that my Exh manifold tends to glow so quickly cos it’s made from 1.6mm wall section stainless steel. I have had the manifold on the engine for approx 3 years now with no problem what so ever. Another bonus of the Exh manifold is that it is so light compared to the stock cast iron 2wd item.