Would be grateful for any experienced advice. I’m currently building a new q35de engine for my g35 endurance racecar. Having trouble getting head gask both sides to seAl at combustion chambers and externally on both banks. New build not cranked yet. Heads have been resurfaced with very smooth surface. Engine never ran hot before. Cylinder block surface excellent showing no unevenness. Checked flat in always less than .002 Checked head bolts for bottoming out with plenty of clearance. Head locating stud are not bottoming out either. They have 1/4 “ clearance. Have tried new oem head gaskets and also .020 thicker cometic gaskets. I have 40 years experience building engines but this is my first vq35de. Pressure tested cooling after eAch change with 10 psi pressure. At my wits end over a presumably simple problem. Thanks.

How carefully did you clean the deck? And what did you use? And are you using a factory head gasket?

Dislocated sleeve? Hidden crack? Have you done some dye to see exactly where the leak is occurring?