I also reduced the inlet area about 20%, adding a diffuser section.  The outlet area was reduced to about half of the original, depending on what kind of bulges on the bottom are assumed to be "standard."  The cooling is marginal, but adequate - on hot days climb speeds have to be increased and cruise is done with the flaps open.  This is to keep the CHT's below 400 and oil below 220.  Closing the relatively small cowl flaps increases the speed by 2 to 4 knots. 

ES #157, Lycoming engine