Some people bring in help when they get swamped and don't check the work of the helpers. I built my first 727 when I was 15 years old and close to 30 more since then and all you need to do is pay attention to details and you will have success. The only failures I had was when the owner installed the converter the wrong way, not being careful with the alignment and damaging the pump bushing or the drive lugs.

Gus