need some help

i am going to build me a bad 318.i have some hogged out x heads , good 318 block and i am going to buy a 4 inch crank.i am needing some dome pistons 12 to one or 11.5 to one if any one can point me in the right direction i would apreciate some help.i have many connections so if any one know of a company or supplier that makes them/sells them

and also how much horse power do you guys think it will make i plan on running a 4speed with 3.55 gears about .510 lift cam and a victor intake with a good holley