Fine Tuning a 360 Magnum with a Brawler "Double Pumper"

First off, let's correct something. It's NOT a Street Avenger. Those are Holley carburetors, not Quick Fuel and they are vacuum secondary, not mechanical secondary like the little Brawler that you have. So let's get that out of the way. What you have is a Brawler, 650 mechanical secondary (double pumper). Alrighty. Now we have that out of the way, I have a question.

WHY did you start by changing the jets?