You using the stock head bolts or studs???
I ask, because I see a thin head gasket and wondering if the bolts are bottoming out, putting pressure on the cylinder walls. Making piston to cylinder tighter.
Make sense???
Place a washer under each head bold, torque to 17 ft/lbs and try again.
You really should spray that thin gasket with some copper gasket spray. I've had a few leak without it, jus my opinion.