Engine builders...this machining cost sound excessive?

I didn't read every post...but there are several problems here. The absolute biggest is 'why did that donkey have it 10 months?' I might have missed something, but assuming I didn't - life is too short to wait for that long for a couple days' worth of work.

Also, your failure to define scope of work and price ahead of time didn't help.

No one should get $80 per hole unless it is Ray Barton or one of the Landy boys, and they are using honing plates, too. The problem with $80/hole is there are 8 of them and 8 x $80 = $640. Tell the machine shop you want their kids to go Harvard but you don't want to pay for it.

Why would a machine shop want to paint a block, and why would you let them?

You know the old saying "You can have it good, fast and cheap -pick any two"? You got one, maybe.