the biggest reason for it , is to keep lifters from coming out in case of pushrod failure. it does help keep oil off intake and directs it back down on cam. doesn't hurt.
I know they advertise it as making more power by keeping hot oil off the intake but the above reason is what I see as the big plus. If your spinning 6000 rpm and toss a pushrod and the lifter kicks out you have instant zero oil pressure. Even if you shut it down immediately by the time the engine stops spinning most likely you will have completely wiped out the bottom end. I put them in anything I plan on hot rodding just for extra insurance
