what are the CC's for the 440 heads

I will not know what heads I have until I pull off the rocker covers, not working with original motor, supposed to be 1970- 440/375hp. What is the factory compr ratio for the 1967-1970 RB motors? the casting numbers on top near dist. is 440-C (block) the heads could be earlier and could even be closed chamber. I want to establish what I have to determine what cam to go with but I am looking at the 275/284 which looks good for street. and Yes the car is a WS23L thanx in advance.