what am i doing wrong?

I don't want to see you kill the motor but I take my 3/4 ton tow truck to 5500 when I jump on it. It's power is at 3000. If you take it easy nine out of ten passes who is to say it wont beak on the tenth. If it was my car I would at least take it two 6300 to 6500. Do it near your house from about 3000 rolling. If it breaks it breaks. I dont think it will. You have good parts and unless the builder messed something up I don't see an issue. Breaking in a motor is not a 100+mile proccess. The half an hour between 1500 to 3000 works just fine. I am sure later on tonight you will hear from a lot of people that have spun weaker motors in the 6k range. Tose heads like rpm. I dont want to lead you wrong here but I don't think I am that far off.