340 valve spring selection

Ummmmmm, what cam is it? What grinder/seller?

Whats wrong with there springs?

If it is a Comp cam, get Comp springs. MoPar cam, MoPar springs. They lined everything up for you so you won't have to. A few pounds increased in pressure may provided for a few more RPM's, but this type of gain is seen at the track and not the street.