That design is at least 40 years old. That means moderate lift with big duration at 50 lift which means low idle vacuum. I think 9 - 10" vacuum at idle is pretty representative as to what this cam can do.
IMHO advancing the camshaft will increase the idle vacuum. If I'm wrong some angel of mercy will certainly tell me so.

http://iskycams.com/cart/index.php?main_page=product_info&cPath=12_14&products_id=148

The cam is not very aggressive compared to more modern high lift cams. It also has 0.028" lash so the lift is really around 0.480". The highest lift Bullet 0.904 lobe for the same 0.050 duration gives 0.578" gross with 0.008" lash for 0.570 lift.

There's the info, do with what you will. I often wonder whether some of these old lazy grinds might be good starting points for regrinds.

R.