Magnum Camshaft help?

Magnum block, Edelbrock heads... looking for a roller cam that will put me in the 450+ hp range, thats easy on the valvetrain (if there is such a thing). This car will be a weekend driver, occasional strip / shame a Mustang type. The motor is going into a Demon with a 2800-ish stall and 3.91's. I had a cam suggestion earlier for a Comp XR286, 286/294 .544 .5.41 (236 242 @.50), and it still seems like a good cam for what I am doing, I was just wondering about longevity of the valvetrain at that lift? Assume hardened pushrods and roller rockers (steel) etc.

Last question, with stock pistons and 58cc Edelbrock heads, how much Compression ration can be gained from decking? A guess is fine...