That's a 302 cam. It will not perform to full potential in a 408. You may have been happy with it in your 393, but that's because you don't know what you're missing.

Just because your springs on the AFRs are good to .600 lift doesn't mean they have the correct seat pressure for the cam. You should match the springs to your cam.

Go with the Scat kit.

______________________________________
There are two types of cars in this world; those with nitrous and those that need it!
Whoever said money can't buy happiness never had a wife with breast implants.