Chances are, if the coolant is dropping but there's no leak or milky oil, it's going into the cylinders which means you need to pull the intake back off and redo the gaskets because there's a breach between the coolant ports and the intake ports.
The header gasket leak is common, but determine whether it's at the head or at the collector. Both are common for having leaks when doing a header swap.
The header gasket leak is common, but determine whether it's at the head or at the collector. Both are common for having leaks when doing a header swap.