If you are breaking axles like that then something else is wrong, the tranny can be misaligned, the bracket that holds the axle in place can be loose, something can be bent.
All you have to do is start binding an axle to get it to break.
FWIW Tom put down a little over 700whp at the tires on a dynojet. We dont count flywheel power on here.
[B]1951 McCormick FARMALL M
2007 MINI Cooper S Turbo... new project car
1998 Chevy 3500 Ext cab, long bed, 4x4, duelly, turbo diesel
2004 Harley V-Rod.... sex on wheels
2011 Harley Electra Glide Ultra Limited