i agree with oldbogie, if you were going to use a 305 head then you used the right pair, 4416's, and as long as you are not planning on making 450-500hp they can be a very good set of heads for the street, their down low throttle response is very good and like mentioned by oldbogie with some port, bowl work and larger valves they handle a 350 till about 6000 rpm. the problem is that many people think that they can take any ole' 305 heads like the 434's and so on and do the same thing, this i would not recomend as they aren't as good of a flowing head as the 4416's and they dont take to machine work as well. you have to remember that the 4416's are the 305HO heads.
and just like oldbogie i have a very hard time beliving in the 190psi, you mentioned 150psi stock and it would have been more like 130psi from the factory. general rule of thumb is 150-160psi is the absolute max on steel heads for pump gas (93 octane) and 170-180psi is the max on alm heads for pump gas (93)