Lookin for a recipe!!

Ok guys Im plannin on buildin a BB for my pullin truck, I know its not A-Body but still mopar. I need to build somethin round 412CI but no more then that. So technically I can use a BB but limited to 400CI because of the rules. I need to build somethin with balls of torque, but have to run a dual plane intake and must use iron heads. I currently hav a BB 400 (406) but lookin for alittle more. Id like to be around 600-650HP with as much torque I can get. Any help would be greatly appteciated