Alton is correct, that they are designed to work at "normal ohm loads" and JimJ is correct about not worrying.
You'll still get most of their power at 8 ohms. If you look at bench tests for regulated amps, they do slightly more power at 1 ohm than 4 ohms. Even JL regulation circuitry isn't perfect... but if you extrapolate the behavior, I'd expect you get around 80% of power at 8 ohms (just a guess).
I'll try to find some amps tonight that fit.