Not a pro builder here either, but I deal with the hot rod community in my job everyday.
Biggest thing I get is guys who always build the car, make tons of HP and then the cooling system is always an after thought. If you are going to make 500+ HP for the street or mount a blower, you will make lots more heat. The stock radiator you got out of the scrap yard will not cool it. When builing a HP motor I always suggest building the cooling system to be able to dissipate the extra heat.