When I was at ATC, we built an extra 500 12" drive units for ACDC to use at the Monsters of Rock Concert at Knebworth. They had 500,000 Watts of amplification and went into the Guiness Book of records as the loudest Band in History.
A year later another PA Company we dealt with used twice as much power for the Pope's visit to Madrid.
I believe Health and Safety regulations preclude the SPLs of those years now but it's might interest you to hear how the Drums were recorded for the Song "For those About to Rock". They used a Warehouse in Wapping, it was a room about 50ft sq. with a ceiling height of a little over 6', the drums were positioned centrally and in each corner they set up PA systems with about 10,000 Watt of amplification and miked them up to the drums. The engineer told me that the sound of a stick rolling across the snare was absolutely deafening. The drummer found it impossible to hear the rest of the band through his headphones so they attached a pair of Auratones to his head with Gaffer tape and blasted him with a suitably powerful Amplifier.
They also had the Largest Church Bell they could get cast made for Hells Bells and 21 American Civil War Cannons made for another track.
They were extraordinarily good musicians for the genre and they took it to extremes that few could equal and I admire them for it. If you're going to do something then that's the way to do it!