3-5" is about all I've been able to get out of our Areospace vacuum pump we are running on the 572.
While running a vacuum pump the engine has to be meticulously sealed. I was talking with tech @ areospace last week about the pump he said the larger engines may not get much more than 5" which is ok with me the main reason we are running it is to control the engine from oil leaks due to the larger stroke. It's doing that no serious leaks last year... well almost no leaks.
plugging the hole where the dip stick went, a Charlies custom oil pan and a new set of Indy valve covers with NO holes except the port for the vacuum made the difference in the pump working or not for us.

we also run the evac tubes on the 500 in the GTX they work great for that application.