Shady Dells give flow rates for most of the various Mopar heads.
http://www.shadydellspeedshop.com/cylheads.htm

They put the W5 in the 320-330 area which is similar to the INDY 360-1. The Victor isn't listed by them on the website but my impression is that it is closer to the W7 which is in the 350-370 class. I bet if you called they would have an answer.