Carbon Buildup 4&8

[TrackRacer]

Having a lot of carbon buildup in Cylinder 4 & 8.
I'm running a 90 302 GT HO with Motorsport GT-40X
aluminum heads, Ford Motorsport B-303 Cam,
1.7" roller rockers,65 mm Throttle Body,70 mm MAF,
24 lb/hr injectors,Motorsport 9mm wires and running
at 40lbs fuel press.. Can anybody give me any hints
what to look for ???

[auto10x]

Perhaps these are the cylinders that get most of the flow from the PCV valve??
auto10x
Bill

[zipzip]

Aren't the water jacket holes adjacent to these cylinders? This may mean a cooler cylinder than the rest. Which will mean more blow by. Check your tstat and water temp. Just a thought...