That is a wild speaker and your current amp is insanely good. To step up from VAC with power you could always look at something like a VTL Siegfried or something of that sort but I am not sure it will be better.
An interesting option, and I mention it because it is very different, is the KR Kronzilla DXL mono. Similar power output and a warmer sound that is between a KT88 and a 300B. They are really lovely amps. The tube replacement cost is painful but the tubes are good for 30K hours so unless you leave them on all the time, it will be a long while before they need replacement.
I have no relationship with VTL. I am a KR dealer.
An interesting option, and I mention it because it is very different, is the KR Kronzilla DXL mono. Similar power output and a warmer sound that is between a KT88 and a 300B. They are really lovely amps. The tube replacement cost is painful but the tubes are good for 30K hours so unless you leave them on all the time, it will be a long while before they need replacement.
I have no relationship with VTL. I am a KR dealer.