Yes

Installed on my 6A....easy. Not sure of the benefit if any for me, but no harm either. I believe it is a standard on 10 cowls.
 
Yep recently installed

Fitted this along with a suite of other modifications to resolve a high CHT on #3 in our club RV9A. Was easy to install.

Will be testing the effectiveness in a fortnight if you'd like to know the results. Easy to mitigate the effects by taping over the vents between flight tests.

Pat.
 
Should not be needed with an RV-14

At the very least, do not install until doing some flight testing.

Highest CHT I ever saw on -14A was maybe 380, early on. Very efficient cooling with stock cowl baffles. Oil runs a little warm, but well within acceptable ranges.