EMG 81 with 2 9volt battery mod 18V!
That guitar must have some serious gain.
I use passive pickups on my two guitars, even though one set is EMG but passive lower gain HZs, and our practice studio has two half stacks and one full stack, JCM 800, JCM 900, and Marshall Custom JCM 2000 and they get the job done.
But the drummer likes to plug in some of his 13 guitars through those rigs and has several equipped with EMG 81s, but 9 volt, and that just blows my freakin' ears out. (He has two Fender American Standard strats with just an EMG 81 in the bridge, a couple of Ibanez superstrats with EMG 81s, and a couple of Jackson Randy Rhoads with EMG 81s. Overall, it's just a little too high gain for me so I never use any of those guitars. I like his Ibanezes, Fenders, and Gibsons that he has with the stock passive pickups with those three Marshalls.
The context of our studio set up has a drumset that is not miked and the PA is either 130 watts or 250 watts, but not really very strong as vocals need more push to be heard over instruments.
The only way I have been able to get a good sounding mix with an EMG was when the amp was smaller or we played in a venue when where the club had a very strong PA if we brought our Marshalls. There is no sense in having a guitar be so loud if the PA, drummer, and bassist can't keep up in volume. That's why some guitarists actually get a better sound in the context of a band with a PA when they either use smaller amps that are miked, for control, or use relatively weak output pickups like stock Gibson PAFs or stock Fender single coils as opposed to a supercharged active pickup.