To meet your specs will be a tough. 500hp pn pump gas? It'll take more expertise than your average engine guy.
May I suggest you contact
http://www.dickmillerracing.com/
http://www.fcrparts.com/Page_1.php
http://www.rocketracingperformance.com/
or any number of reputable Oldsmobile engine builders. Just stay the heck away from Mondellos.
C.J.