The other alternative would be to open up the openings underneath and use the already high pressure air being forced under the cowling to assist in being drawn into the cowling, and install vents near the firewall baffles, closing off the openings in the front behind the prop. If you look at the illustrations of the areas of pressure as shown on Mark Langford's site you will see how the high pressure zones are all over the bottom of the cowling giving a natural ram cooling effect. Robert Finch also talks about how this was very successful in Jess Meyers' first efforts with the 4.3 V6 in the RV6, and also a Jaguar homebuilt. By baffling at the bottom of the engine and forcing up through the heads reversed, you might even increase the aerodynamics some by smoothing the area right behind the prop where it is so blunt and allowing a more streamlined scoop vent on the bottom. Food for thought...
Colin Rainey Sanford, FL N96TA