Part interchange?? 289/5.0??Heads??

[shark7000]

I've been reading about how 289 heads having a lower volume, causing higher compression. The newer 5.0 heads will give a lower compression, and the GT40 heads are, of course, the best, with higher compression and better flow, resulting in more ponies to the wheels. So, I'm guessing it's a better idea to not put the 88 heads on my 67 289. Any input would be greatly appreciated.
Thank you,
Mark