Got a puzzling issue with my NA 6port, changed the exhaust manifold gasket and noticed the exhaust ports are a dull white inside the block but the normal dark color in the exhaust manifold and my AFR gauge reads actually a bit rich.

Anyone have any ideas as i'd say a white exhaust port is lean? But I have read the 6port has some sort of insert in the exhaust ports?

 

welcome to the board.

i would believe the gauge if you're not having any actual issues to suggest otherwise. i've seen some engines show that light-colored residue in exhaust ports before, but never knew why some engines did and others did not. you might want to check and see if you're losing antifreeze.

all engines have exhaust inserts or sleeves. if it's something 6-port-specific, then maybe you're referring to the diffusers, which are the little winglets in the sleeve that are there to help cut some of the harsher frequencies in the exhaust sound/volume.

 

if the sleeves are dark brown to black, then your car would be very excessively overly rich. ie, it's normal to have cream color sooty sleeves.