I think the reason you aren't getting more answers is the question is too vague
"How drunk can I get until I am too drunk?"
A cam is a trade off, just like the gears on a bike. Is 1st gear or 10th gear better? It depends if you want to go uphill or downhill. As you add duration, or change any cam characteristic, you gain somewhere and lose somewhere, and it has to match end use and other parts to be "right"
If you are asking about your Cobra, you are likely somewhere between the 224 duration range to the 250 duration range, however, the bigger you get, the harder to tune (or at least you need a good EFI system and some practice with it), and less low end you will have, and to quote our president, the difference in that range is "YUGE"
Try not to think about components, think about systems, where do you want your whole car to behave? idle to 5000, with most of the time cruising? most of the time on I-80 doing 80? 0-100 at the dragstrip with a peak of 6500 and a 6900 rpm shift point? Little or no concern about tuning? All of these are "perfect" for one owner, horrible for another.
Also, remember the cam alone doesn't determine RPM range, intake, exhaust, cam, even the tops of the pistons (less on an FE than others)all determine how deep it breathes. And if given the choice over big cam, bad heads, or good heads, smaller cam, I'll pick the latter on the street
Here's something that will go against a lot of normal logic. My short bed F100 4x4, had a stout 445 in it, likely 500 hp range and pretty much matched well. I temporarily put a nice little zero deck 390 in it, baby cam, likely 350 HP. The truck is more fun with the little engine, little cam, to the point I am rethinking how (and if) I am going to do the 462 on the stand. It pulls hard, makes nice music, just less than the 445, but it fits the truck real well
Now for you, say your engine is 440 HP, a cam swap gets you to 475, you need to think through where you pay for that. Good thing on a Cobra, assuming you have a high end EFI you can adjust, overcamming isn't as bad because it's light, and loss of bottom end can help with traction. However, go too far and you may not like in town and 5th gear. Also, I mentioned it earlier, remember, add a few hundred RPM for a shift point, as you get above a 5800-6000 RPM HP peak, you start getting to where parts matter a little bit more if shifting at 6400, and who knows how Dove built that motor.
