So pistons sounds the most appealing to me. If I can run the engine just with new pistons I’ll be happy. I just have to make sure this WILL work and have some kind of useful power.
That 'lack of useful power' is not directly explained by the excessive CR, unless the engine was perhaps detonating all the time. A 408 sure ought to have good power! Regardless, the CR situation needs to be address.
BTW, it is still important to let us know what you want this engine to do: cruise, pure race, haul logs, or ?? The cam's appropriateness comes from the application.