I think you'll hit your 500hp. Peak will be at about 5500 rpm, which is right in a comfortable spot for a hydraulic roller.
It should be a nice timid street motor with lots of power.
If you ever decide you want more power, trade the heads off. If you can budget a little more, go with a set of AFR heads. You'll gain a lot more power.
That amount of horsepower is a lot, especially in a tiny car, but I always advise my customers to aim a little higher, because you get used to it after awhile and wish you had a little more.
