I can think of a lot of things I don't feel like typing. The list is too long.
Whats the combustion chamber volume on your heads? (or casting number)
What kind of valve springs do you have?
What do you have for a fuel system?
What jets are in the carb?
What ignition coil are you using? (do not use the red blaster)
Last year I built a 468 for a '75 nova, it ran low 11's easy but is was a very well planned build. I had a 6000 rpm chip in the MSD. More compression, bigger cam, intake, carb, oval port merlin heads, 3" exhaust, but otherwise close to what you have. Here are some pics of my build up.
It was kind of weak at first, I went from a 750 carb to 850 DP, 2 1/4 exhaust
to 3" , stock 5/16 to 8AN fuel line with a 172 GPH carter mechanical fuel pump. and it woke right up.