Cubic inch don't build hp, air flow does, larger Cid engine just gonna make lower rpm Hp. A 550hp 500+ engine is probably similar top end parts list as a 550hp 440 just gonna take a 1000 less rpm to do it. I'd start with heads selection at the 2 cfm per hp rule would put you at 275 cfm heads but I'd look for a head that flows around 300 cfm at a reasonable lift to be able to go with a slightly smaller cam and compression ratio. Once you pick your heads you can zero on the cam needed. Since you want a lot of lower rpm torque a ported eddy rpm intake or something similar.