[chiphead]

I always use 1016 gasket and ARP bolts with iron heads.

Have the heads been checked for cracks? I could see a head crack making you chase your tail.
Has the depth of the block's bolt holes been verified?
Is the torque wrench known to be good?

You have to ID where the gasket fails to prove the gasket seal is the issue. Where is the leak happening in the gasket?
Is it at the fire ring between cylinders, or between a coolant passage and the oil galley, or between the fire ring and a coolant passage?