Let me pick up on two things that Tim said.
I'd recommend going beyond having them Magnuflux the head and have them pressure test it. I recently had one pass the Magnuflux test be fail the pressure test. It had a pin hole leak where hardened exhaust seats had been installed by someone else.
Hot tanking rarely cleans out the back of the block where the rear drain is as Tim mentions. This takes mechanical digging to clear. I have a hunch that many blocks get rebuilt by shops without going through that step.
There are two additional items that I'd recommend. Have them drill and tap the crank snout so that you can add a bolt to the harmonic balancer. You can search that subject and read about Hotrod Lincoln's kit to do this task, but you might as well have the machine shop do it when the crank is being turned. And have them modify the timing plate per the link to the below Tech Tip. It is easy to do when the engine is torn down and you'll be glad you did it if you ever have to pull the timing plate in the future. The only thing that I do different than what is described in the Tech Tip is that I use 3/8" fine thread bolts instead of coarse threads.
http://www.stovebolt.com/techtips/timing%20cover%20mod/And I don't think that the price seems outrageous. If you want to compare, you can go to Deve's link below to see copies of invoices for machine work on a 235. That was for the machine work only with Deve doing the rebuild.
http://devestechnet.com/Home/Project1959235Matt
