Whats the best intake manifold for me???

Ok the car is at my dads house i cant tell you about the cam until this weekend but when i said x heads i meant in 72 they had the low compression j heads (correct me if im wrong) and the earlier 340's like 68-71 or somethin had the better heads they are cast iron i think...no porting done but when the cam went in it had to get some heavier springs etc in the head i will try to find out more information, thanks for the help. any knowledge anyone would like to share is much appreciated.