frame strength

i have a 70 firebird that i would like to give more strength to the frame, for i am looking for much more power...can i get pointed in the right direction as to start researching what best fits my standards...thanx

http://www.jegs.com/webapp/wcs/stores/servlet/product_10001_10002_56720_-1 I'm adding these and the matching weld in connectors.