i currently added the edelbrock performer kit which is 650 carb intake and cam hyd lifters 270 duration...i am getting some edlebrock rpm heads and a bigger cam..hbow big should i go? should i get the rpm intake or performer will do? also flowmaster exhaust going in too...anyone care to estimate horsepower output>>thanks guys  

Depends on compression and intended purpose for the car.
If your gonna use those eddy heads you might as well use the large port rpm/air gap.
If your a lead foot cam lift/duration in the range of .500 278*-282* and would also throw 1.6's on it.
Thats what I think so far.
Really with those heads [+ 318] I'd like to see 11.1 compression and 108cl .540 288*-292* lift/dur range then you would also need 3.91-4.10 gear and 2800 stall if automatic.