Any carb sucking hot under-hood air can benefit from cooler outside air and I always picked up but had to make tuning changes.....Then there's turbulence in some cases where the WRONG scoop can play havoc on bowl vents actually pulling fuel out of the bowls at speed etc..........
I was going to say the same thing and have a couple of things to add:
* Any results you see can also depend on how the car is jetted to begin with. If it's a little rich, it can pick up. If it's a little lean, it may not help, or hurt.
* Underhood air is more "consistent" than scooped outside air. In theory, a car without a scoop will be a bit more consistent/predictable than with a scoop. I had a friend & VG bracket racer who actually blocked off his '68 Cuda scoop with clear plexiglass.
* Another friend had a '65 Plymouth with a correct Hemi style scoop over the 360 that occasionally did weird things. After unsealing the carb with vents in the foam, the problem went away. Inconsistent turbulence was the only thing we could think of.
