Help me build my 340!

Going to be rebuilding my 1970 340 for my 1969 dart swinger. I'm look for 450/500 horse and im looking to save as much as possible as im also restoring the car and its almost done. The motor has a set of x heads, edelbrock air gap intake, an eddy 750 cfm carb, stock cam and stock distributor. Any help is appreciated, thanks guys!