I use the lunati 305 which is the next step up from your cam and it's always good for 500-520 hp.That's the cam I put in daily drivers for guys who want ZERO maintenance.
That 304 cam was always 30 to 40 hp down from the 305 depending on what parts were matched with it..
It's a nice street cam...smooth idle ..good power from 2000 RPM right up to it's red line...nice and flat.