In need of some 273 head education

I love my 273ho, i just rebuilt her but need to take her apart again and replace the head gaskets. My compression was lower than it should be and i thnk the head gaskets might be to blame. Also i want to check everything out to make sure nothing is damaged. I had the heads completely rebuilt because the valves were really worn. The keepers were diggin into the valves making it have improper valve lash. The guides were worn as well so rebuilding to stock was what i wanted. I plan to port the heads when i take them off this time. This will give me time to make sure i put everything together the right way the first time:) I like trying to make the stock engine do things others don't think they can do.