Looking to buy/build 500-600 fwhp 360

I have a couple 489 chunks! I'm trying to reduce the unsprung weight of the car. I'm going to fill the tires with helium. If I still break the diff I will just go with a chevy 12 bolt.
8 3/4 with a 4 speed and 500 hp ? forget it , just get a Dana END OF PROBLEMS