We've tested the extra airflow and it reduces engine temperatures by an average of 10 degrees, increasing power output and extending powerhead life. 
 
These louvers provide extra breathing like the original Mercury Racing 300 Drag and S3000 over stock or non-vented cowlings.
 
These outboard cowl racing louvers can be easily mounted inside a relatively flat area 3.5" x 10" area.
 
Set of two (2) with two (2) small Buckshot Racing #77 decals.
 
Contact Mike Hill at STVracer@yahoo.com