Highest flowing sbm heads?

mysself why do all the crazy money stuff
416 comphy 240@50 rhoads lifters eddys air gap 750 dp 11 to 1 8.9 dcr good exhaust
450 hp at 5400 ish twin stage 200 shot 3k verter 27 tires 3.91 gear vend od
pretty cheap should run low 11s get 20 mpg