[Rory McNeil]

I can`t speak for GM & MoPar, but I`m not aware of any of the Fords having different factory HP ratings between Ram Air, cold air, Shaker, whatever you want to call it. I`ve owned several factory "Shaker" equipped Mustangs, 69 & 70 R code 428 , and 70 351 Cleveland 4 barrel, the factory ratings were 300 for the 351, and 335 for the 428`s, same as the non Shaker cars. Same with my 69 Fairlane Cobras, 335 with or without Ram Air. However, in the 70`s, until the early 80`s, NHRA added 5 additional HP for the 428 CJ ram air cars, over and above the considerable factor that they had already added to the 428`s. Basically almost everybody who was running a 428 CJ car at that time replaced their Shaker or Ram Air hoods with flat hoods, rather than carry the extra weight the scoops required. As for hood scoops in general, obviously not all are equal in design. The huge 68 Hemi Cudas and Dart scoops, as well as the boundary layer designed 440 6 pack Road Runner and T/A Challenger scoops would likely be superior to, say, an 68-69 Road Runner "Air Grabber", Buick GS, or Firebid-GTO style units. I remember towing a friends 70 Buick GS to Boise , on an open trailer years ago, in a rainstorm. When we got to the track, the rain and dust had left a nice bunch of trails on the hood, & by looking at these dust trails, it was obvious that the airflow went around the almost flush hood openings for the ram air setup, rather than into these openings. Many of these scoops and "cold air" setups were simply styling gimmicks, while others, most notably some from MoPar were actually designed to be functional.