Your .557 camshaft should actually measure in at 257@.050. You would be making a pretty large change going to the Comp grind you are looking at.
It's probably not a bad choice,but you will limit the top end quite a bit compared to the MP grind.
But it really depends on what you want to accomplish.
Do you know where the installed centerline of the MP cam ended up? They recommend it in at 108,but with a street car I like to advance it a couple more degrees. I always thought that grind made pretty decent torque,so I was wondering if it was unintentionally installed a couple degrees retarded now?
Keith