I see your point but agree to disagree lol, if it really was a big deal on a 4.6L mod motor with the way we mod, we would all have run out and did the vac pump mod on our setups. The point is on a small boosted v8 breathers do the job just fine. And if you were losing any power in this case it would be neglible, but as most others have found out going to breathers on a boosted setup for our cars, actually frees up power. Really no need for vac in the crankcase when theres boost in the cyllinder, that piston is coming back down on the downstroke regardless if theres vac/atmosphereric in the crankcase!
On an all out n/a car/stoker etc, sure i can see a vac pump making a few hp. Im perfectly content with my breathers.