I'm on nobodies side here but my own. That being said, the time just to clean all of the parts is worth a lot! It is time I hate.
I used to charge a grand to assemble a basic engine. It kept a lot of the entitled chevy guys away.
I would never assemble something that I didn't do the machine work on myself. I would not assemble even a stock 318 if the customer did not want it balanced.
Although I liked the work, I had 3 kids to feed. Tooling costs for a shop are outrageous. There are a lot of unbillable hours when you do it for a living.
Stock or race, the guy putting it together has to be on top of everything, you cannot afford a single failure.
Just my thoughts, for free take it for what you paid for it.