compression of a stock 1968,383????,

I'm just looking for the rough numbers on a 68 383,, Its bone stock,, its got 906 heads, has not run since 1974 except for when I tryed it out to buy it. I know I have to rip it apart to re gasket and seal it but I was thinking about doing a little bit of internal work while it was apart but I don't want to go above 10:1. so if these are already a high compression engine then I wont do anything except bolt on's. Thx in advance