Anyone can get a bunch of parts and bolt them together.
It takes someone that knows what they're doing to coordinate camshafts, cylinder head specs, know what needs clearanced and where, know what to check, have the right tools, etc.
There is also a difference between a machinist and an engine builder. I don't do any of my own machining, but have a machinist that I work very closely with. I know how he does his work and he knows mine. I check my mics against his regularly. He also follows my instructions to the letter.
I don't turn out a lot of engines for a reason....I worry about each and every one. I can't afford a heart attack at 32...
I also don't sell an engine without a dyno session just so I know that the engine was right before it went in the car.
And I never use flat tappet cams.
