Hello having issues with recently purchased blown 427 in 32 coupe, Initially car only had 16" electric fan, knew this would not work ordered new fan with custom shroud, temp gauge would not work, figured out had air around temp probe would bleed air off and would work a short time then stop again with air around it,did block leak test and indicated minor amount of combustion gas in coolant, thought head gasket , tore down nothing obvious wrong with gaskets, both #5 and # 4 piston tops were very clean, reassembled, doing same thing, I have a set of 1971 LS6 heads when looking into both #5 and #4 exhaust ports i see there is a passage that goes up to where intake gasket mates to heads I am thinking that these passages and clean piston tops are definately related but not sure where problem could be, engine only has 230 miles on build,also both spark plugs in those cylinders appeared sooty, have recently did radiator pressure check and does bleed off from 17 lbs to nothing in about an hour no visual coolant leaks, bought scope to view in cylinders cant see anything leaking but really cant view entire combustion chamber any help would be appreciated only put 35 miles on car since buying in June really frustrated thanks