HP limit with 1-5/8 headers

I read the article that GotDart posted and it is very interesting what Ed's headers says.
One very important factor is where I will be running the car-Bandimere Speedway is at 5800' in altitude. That is why I am using 12:1 static pistons, however the cylinder pressure will be more like 11:1. It seems to me that it is very easy to over do it with cam, carb and ports up here. I will be experimenting all the way until I sort my combination out. My goal of 450 hp is more like 400 up here, and I am really looking for the most mid range torque I can get. I feel it will be easy to overpower my 8" wide drag radials with too much low end. I went with 4.30 gears and I hope I haven't over geared the car.