JZX NZ

Does anyone know where can I get a aftermarket camshaft without changing the valve spring? Prefer 272. Is that ok if I only change the EX side instead of both side? Does it make a lots of gain?

I definatly would not recommed putting a cam with that high duration in without changing your valve springs, they will almost certainly coil bind. You would make some gains but not a huge amount. But yes you can change one side without doing the other.