[blykins]

Here's where I am on it....

You're getting ready to add ~50 cubic inches. Your existing camshaft, even though it peaks at 6500-6600 now, will be "tamed" down by the extra displacement. My guess is that with a 408, the peak hp would be down around 6000 rpm.

To be dead honest, I would use the camshaft you have and try it. I think I could do better, but I don't know if I would make it that much better to justify a $425 purchase. A lot of my dyno testing is just A-B camshaft swaps and I've learned a ton, but there's a point where you just need to run it and see what it does.

As for more horsepower, I would look elsewhere at the car to see where you can get more power. The first place I would look would be the exhaust. Sidepipes on Cobras can be atrocious and it's not uncommon to see a 75-100 hp loss at the wheels because of it. An automatic transmission with a higher stall torque converter will also soak up horsepower on the dyno.

You're going to gain a lot of lower end power and torque with the 408. I think you'll be happy.