On my 440-6, I went with a hyd. flat tappet cam with about 250 degrees of duration (@.050") and .550 lift. I ran long tube headers as well. What made a HUGE difference was having the carbs dialed in by someone who specifically knows six pack systems really well. Most of us know how to change, jets and power valves, but there are guys out there who know what factory 3x2 systems need to work with a bigger cam. I had a NHRA Sportsman Class guy do mine, and it was night and day.

As far as your camshaft goes, the duration on the camshaft is what forms your power-band. You're running good heads that can easily take advantage of more duration than you're wanting to run. The limiting factor in your combination (as it relates to a cam choice) appears to be your stall speed. With 2000-2500 rpm stall (perfect for the street) I think you're going to want a camshaft with between 230-240 duration at .050" lift on a 440. Any more duation and I think you may need more stall to match.
I agree an LSA of 112 may be a good choice for your power brakes. A general rule of thumb is that the tighter the LSA (bigger number) the more tame your idle characteristics will become and more engine vacuum you'll produce. So an LSA of 112 will idle smoother than say a wider LSA of 108 degrees.