Speed master LA heads

There is something that I do not understand. Old Kimmer says that those big port alloy heads are no good for a 318.It appears that he says they are to big for a 318! I have a 318 bored 40 thou so 326 cu ins. That is fouteen cu ins less than a 340 . But they are great for a 340? My 318 (326) has my ported heads off my 410 after I put my Trick flows on my 410. They have 2.05 inlet valves in them and the car has 2.93 diff and real tight std converter and weighs about 3600 lbs. It does not go crazy with wheelspin but is very responsive and goes really hard mid range and top end. Even the police package 318s had 360 large port heads on them so what is this they are no good for a 318?