Head Casting Question

Hey I stumbled onto a set of heads for a very good price, FREE. I am trying to figure out if they were worth the effort to go and get them and use them on my 318 for my wife's dart or to use them for boat anchors. The last 3 in the casting number is 973. Keep in mind that I have the stock set of 302's. There is a big " F " forged in the the intake channel on one of them. Anyone got any ideas 1/4 mile or Lake bottom ???

: P