why J heads, why not x heads?????

x heads are more money, and are harder to find. for h.p, the 2:02 flow better, but what kind of h.p are you looking for? like i stated in my p.m, i was told that it was better to go with 1:88 j-heads, due to if you have a set of 2:02 heads and the valves are "sunk" then it costs too much in the long run. but if you buy a used set of 1:88 j heads, you can just get them fitted for 2:02 valves while you are getting them rebuilt. just what i was told. someone correct me if i was mi-informed