Blue pill or red pill = 675 or 920

Thank you, I'm not in a hurry to do this. I figured it'd be wise to have them checked by a machine shop. Again, the 920s look a lot worse than they are - the 675s actually have some pitting around the exhaust flanges and as I discovered one of the heads also has a heli-coiled exhaust stud. In the end the difference between the two is probably minimal? I couldn't find that info, but did the horsepower rating for 273's or 318s drop from '67 to '68?