MY 2 cents. together I have been an automotive technician and technical instructor teaching engine rebuilding for 45 years. I have a home shop and I build engines for people. I do about 10 engines a year. First a big name engine builder does not guarantee you anything. I have freshened and fixed several engines from those big name builders. Taking the time to measure and check things is what makes the difference. Time is money and when they are building enough engines to make payroll and the bills things get rushed. And I get many people who bring me a pile of parts, and I assemble the engine, sometimes I call them and say this and that are junk, but that's the way it is. Second when you buy that pile of parts, you determine how much HP it will make, the assembler just makes sure it will stay together. Picking the parts and giving the specs to the machine shop you want them to be, is the secret to making power. Kocking on wood my NSS 514 engine has 600 runs and ii is on the stand for freshening and it looks like new inside. Valve springs lost 30 lbs and one exhaust valve is bad. It runs 9.7's And I just have a metal building out in the woods.