Only way to do this is get a "detailed" quote on what EXACTLY is going to be performed. Someone saying all block machining, that's pretty broad statement and it may include a potential line bore.
Just having to pay $1200 for prep and machine work is expendo to me.... it also seemed like he was way behind on work. Being just "Yo" and his worker kinda makes me think it will be there for a while sitting.
If I go to Brian H. I can not only bring the block to him and feel confident, but I can bring my dirt bike out there for the day and do some backflips!! LoL