I've run that same cam in my big van. With the 305 heads, I only pushed 10:1. It was a bit touchy in the summer months with a slight ping. That's when I would have to spring for bigger octane. It doesn't help That we have winter blend fuel and then summer blend from the pump. I don't dare play with the add packs I work with. Since I'm not the only who drives it, I don't dare trust anyone else to put the stuff in. I just drive it for what it is and keep it running.