Dave, I really can't give you an accurate answer on the vacuum a standard engine pulls as all the cossies i have dealt with had, had Cyl head previously machined/lower comp etc.

I'm shore there are people on this forum that would have a near stock engine that they can post the vacuum there engine pull and compare to yours.

The cossies that were tested that were "chipped" with a set of greens were all runing an A/F ratio between 11.8 to 12.5 to 1 at idle. This is rich but it seems its a price to pay for the benifits (extra HP). I am not shore what these figure relate to in CO's for you to compare your figures to.

J