Truth or hoax
Well first lets talk valves the 304 heads had smaller valves than the 360 so their is definately not any advantage. Now lets talk about compression and cc's. The 304 heads 70 and some 71 had a lower combustion chamber volume than later common 360 heads #6090 and #5020. the heads you are looking for are rare and you can look at this chart for help. The advantage is making more compression by using a smaller chambered head...the disadvantage is that they use smallish valves so the high end suffers
