blowing anti freeze out the overflow

Morning
I have a 2003 C15 550 cat. New turbo new injectors new CAC new cam new exhaust system manifold muffler and so on. the head is a year old. Replaced water pump and thermostats with sleeves new radiator as well. closed off the water ports from the air compressor to see if I was getting pressure from there no change. I have no cross contamination no anti freeze in the oil, no oil or fuel in the anti freeze. This motor is a high mileage motor the head was put on at 1.4 million but the liner protrusion was good 3 to 5 thousand. I found a thread on doing the compressor test and will be doing that, just to rule it out as it is new as well two months old. my question is can cup seals put combustion pressure into the cooling without contamination. I kind of feel like I may have a cracked liner because I have no white smoke out of the exhaust and the truck has been running the same no change in performance at all. the motor is at 1.6 million and I had hoped to take it to two million without an in frame it uses a gallon of oil about every 6 thousand. I figured if I had a liner drop it would have showed up in the exhaust with white smoke. I don't think the head is cracked because the pressure is building the minute you start the truck no matter weather hot or cold. any help or advice on this would be great thank you.
I would like to say thank you to Mr. Haney and everyone who has posted all the performance mods and add on for the cat motors. it helped me take a MBN 5.25 mile to the gallon turd cat to a 7.25 mile to the gallon cat, hell yeah and power to boot. these are the mods I made. Turbo non gated compressor-175958, turbine housing-171698, cartridge-175964 C16 turbo-175963. PDI exhaust manifold. 10R8501 stock injectors 6NZ cam stock. 1999 stock 550 HP tune from Caterpillar and a free flow muffler from Pittsburg Power. I have run this setup for a year now and it has already paid for itself. I tried to go for less on the power and more on the mileage side of things and its really worked even better than I had hoped for.

 

Yes new headset
I was ase diesel for 14 years before 22 as a driver