What cam should I get?

I bought a 67 Barracuda about a week ago with the 273. The motor was installed in July and is a fresh rebuild. The cam however seems to be to mild for me and I have a 4-speed so I can to a bigger cam without no problems. I know that I don't want to go to big because of the (far as I know) stock valve springs might not be able to handle the cam. I like the Mopar purple shafts cams since I had one in a 68 Charger and it sounded and performed great. Would a 484 lift be ok with stock valve springs or can I get away with a low 500 lift?