bareskinchevy1500

i recently bought a 1982 chevy silverado swb and planning on doing a 5.3 ls swap with twin turbos,4l80e trans and posi 373 rear. im starting tear down this weekend and have a fuel questions, im putting the 5.3 out of an 07 silverado, 53k miles, has 706. casted heads, ls1 tech says they are not to far off from the 243 cast heads, im looking to make 800+ rwhp. is it eorth building up this heads from milling and polishing or should i just buy some afp cnc 243 cast heads? second question the truck has duel tank set up and i want to keep it that way run pump gas in one for every day driving and e85 in the other for racing, what do i need to do for both tanks to be able to fuel the motor with that much horse power? any help will be great and if i have posted in wrong forum plz dont be the person who post wrong forum, let me know where i need to be, im use to car guys helping car guys not being an ***, thanks