i have a similar setup on my daily driver. it is fuel injected, but a similar concept involved. i drive a 2003 **** lightning, and i put a large conical air filter on it to replace the stock airbox. i flt more top end power, but it was definately sucking in hot air from under the hood. a gereal rule says that for every 10 degrees you can reduce intake temps, a gain of 1% hp is realized. i fabricated a heat sheild out of thick plastic to block the heat, with rubber weatherstripping aroung the top to seal off the top when the hood is closed. i then ran a 4" duct from behind the grille to the bottom of the heat sheild, supplying fresh, cooler air to the intake. i did notice some gain with this setup, and the truck seemed less slughish to take off at lower speeds. i know this is mainly qualitative data, but it definately can't hurt. i can provide pictures if anyone wants to see.
