my engine is currently getting bored,new guides and valve seats. At the overhaul shop they boiled the engine is some solution. Most of the paint has been removed and the block looks really clean. I will do the remainder of the work at home. Definitely make sure all ports are clean and free of dirt etc. Good building.

Due to modern guidelines, I don't know of a machine shop nearby that still actually "hot tanks" any engine blocks or other parts. They use a type of cabinet or rotary drum that cleans the parts with a type of bead. I still use a pressure washer and go over the block and it's water passages after bringing it back from the machine shop for the engine build. And I keep washing until nothing but clean water comes out. usually spend an hour or more to accomplish that while continually turning the block mounted on an engine stand, then I blow dry every part and passage.
I also do the same procedure before taking the block to the machine shop, using pressure washer cleaning solution.

My machine shop uses a hot tank to clean parts, but I use a gasket scraper to remove the thick crud first. I then use a wire wheel to finish cleaning and remove rust (after I bring them home), then wipe the parts with Prep Sol before painting.

Also, remember the splasher engines are a different animal in that they have babbit bearings. You will need to find a shop that is familiar with how to do those type bearings. I had to send the 37 rods and main caps off to have them re-babbited and then had my shop line bore the mains to fit the crank journals. Not a big deal, just need to find the right shop to do that work. Also Hudson has very tight tolerances for those, I think .001 if I remember right.