difference between these two cams?

It all depends on the lobe shape - and duration at .050 doesn't tell enough. I'd put a smaller Bullet lobe ahead of a Lunati. Bullet's got some great stuff and there are lobes with similar duration at .050 that carry a lot more duration towards max lift. Some have special ramps to keep the valvetrain more stable with bigger areas under the curve. Saying they are identical is like saying a cheeseburger is the same at MacDonalds and Ruby Tuesdays because they both have cheese and beef.
With those headers I don't think you'll have an issue with the exhaust emptying the cylinder. But I do think you're leaving some power on the table and not getting anywhere near into what the heads can do for you. Those grinds will be great mild cams for you.