My engine made peak torque @ 4750 and peak HP @ 6500 there fore in my application the engine is fabulous(just my opinion) from 4,000-6800. You Cam is about the same as mine.You have a bigger intake and a little smaller engine.I would guess that from 4300-7800 would be a use able range,especially if you road RACED. I wouldnt spent a lot of time at 7800 with out shaft rockers,though Im sure your girdle system is just fine.The only thing I would even consider changing on your car would be a 5 speed. Your car is more race oriented than mine. probably makes as much or more power too.
I would have a couple chips for your ignition too. a 7500 RPM chip would keep that engine glued together with it bordering on too much power for daily use and not rain friendly.
Have you driven the car hard yet?