Help decoding a holley carburator and 99 fastburn heads info

Just got this good deal on a carburator from holley, owner said it was a 700 cfm carb double pumper..but i cant find the part number anywhere...it lists... Holley on fuel inlets.. than 10562 on bowl spacers 10561 on the other, than on main body it says 6R (3752) B....does anyone know what type of carb it is.. also i got some fastburn aluminum heads from same guy dirt cheap 300 bucks for carb and heads, they are 0-12367712 b871-4 gmpp 1829a zeus, i was planning on putting these heads on my 69 chevelle with a 350 engine that guy said i was supposed to use the vortec intake on it..i wanted to get more info before i put these in there..does anyone know what intake i need for these heads