Outer Limits 4x4 Board

i have a GQ 4.2 diesel, just fitted a turbo glide system
to it 600k ago, running 13psi boost. engine has 375000
on the clock. just wanting info, my inlet manifold gasket
is leaking oil!!!!!! is this sinister or just a gasket????
it blows no smoke through the rev range, aside the normal
black sooty stuff. oh and just had dyno tune 500k ago....
any input would be appreciated...