Help identifying pistons and cylinder heads

It makes me wonder and I tend to over think, but was it that they needed heads and thats all they had, or did they think they were "upping compression" and didnt know bout the ports and the smaller runners or did they even care I suppose it doesnt matter but I had someone on the interwebz tell me to "put 318 heads " on my 340 because it will "raise the compression" and I always wondered if they were serious or...:)
Just to clarify, it was not me who assembled this motor like this...I would have never done such an idiotic thing lol. I can understand the port velocity thing to an extent, but a 360ci engine needs to breathe, regardless how "mild" it may be. That's just my opinion.