This experimental study measures the detailed heat transfer distributions over the wavy fin channel with twin flow exits that simulates an elongated flow passage in a fin array. Heat transfer results acquired from the wavy and flat fin channels are compared. Impacts of Reynolds number (Re) and the undulant surface on heat transfer distributions over the wavy fin surface in the Re range of 500-11000 are examined. The spatially averaged Nusselt numbers (Nuav) over the flat and wavy fin surfaces are analyzed with the empirical Nuav correlations derived. Within the Re range tested, the lack of traversing flow momentum over the undulant fin surface prohibits the overall heat transfer elevations from the flat fin levels. Increments of cooling power available from the wavy fin surface due to the surface enlargement only develop at the test conditions of Re>6000 for the present test configuration.