I assume it's just a memory point so it shouldn't take much work, but the current exhaust points on the blackfoot appear to be coming from the top triangular vents... which are actually intakes...
Air is taken in by the top vents blown down by the rotor wash and in by the side intakes which take in air as the aircraft moves forward and then exhausted downward on the sides of the aircraft's tail as shown in the below image which means exhaust heat shouldn't be rising from the top but rather down out the bottom where it mixes with cooler air and dispersed by the tail fan as it moves forward.
Diagram of intake/Exhaust: http://i.imgur.com/NphKhQD.jpg
{F20098} {F20099} {F20100} {F20101}