Cracks in AAN heads

[S4Pirate]

I had some cracking in 2 of my spark plug holes, that went up 3 threads or so. Would it be ill advised to build this head (oversized valves, porting) with that being the case? Trying to get my ducks in a row for a 34 psi e85 tune.

[4v6]

Cant say on the 20 valve heads although ive seen a fair few that do exhibit those same cracks, but on the 20 valve motors the specified acceptable crack width is 1mm and iirc no more than 10mm deep.
Id need to check that depth spec tho to be certain.

I suppose you could get the head pressure tested or Xrayed/NDT tested just in case?