360 cam upgrade selection

Thanks all... My current cam is the crane .454/ 272, 216* @.050". Is the biggest holdback with cam selection the Valve springs? I do have a new set of the MP 542, Orange stripe dual springs in the garage. I wasn't really planning on pulling the heads, but if that is my limiting factor in cam selection, I could pull them and have the spring seats machined and re-install the heads with the thin head gaskets.
I have run the Comp 280/480 in my last motor and it ran really well. I was looking for something more than my current cam to take better advantage of my converter. I also thought that the MP .474/ .484 cams ran the equivalant springs as the 901's, which is part of the reason why I thought of using the Purple Plus grinds.