check that, it should be 425hp and ~488hp check that, it should be 425hp and ~488hpThe HP output on that website must be a typo. The 6.1L underneath it is listed at 425 also. If you go to the Mopar Performance homepage for that same part number, P5155513, the specs say that it is 426ci motor with over 540hp and 530ft-lb torque.
http://www.moparperformanceonline.com/p-1255-mopar-426-hemi-540-horsepower.aspx