How much for a head gasket replacement? on 1990 Subaru Loyale

Everything's fine 'til the engine warms up, then there's a plume of vapor from the tailpipe. It's definitely steam, as it smells of glycol & dissipates right away. However, the motor oil isn't milky & latte-colored.

Asked by for the 1990 Subaru Loyale
both heads with all the required work runs around 1600. if the heads are cracked, add another 400-600