Dan H question on cooling air volume ?

[Larry DeCamp]

I get the idea of Vi/Vo regarding velocity recovery at cowl exit. My question is exit area vs inlet area.
My SJ inlets are 3 3/4" x 2 = 22 SI. My stock cowl exit is about 44SI net of exhaust pipe section area. Engine is 0360.
So, for a starting point to modify the exit, what would be a conservative adjustment to exit area for improvement ? I need to cut and glass anyway to clear exhaust turn downs, so would like to improve outlet in the process.