Ive never had anything crusty enough to feel the need to chase or run a tap down anything and its never caused me a problem. I will spend 2-3 hours cleaning a block after the machine work is done and use a good SS brush in all holes. Brake clean each hole and blow them out then after the 2-3 hours do the finial big soapy wash. So myself have never seen the need to chase every thread, hole, ect.
If you just spent $1700 on manchine work on a block Id hope the shop might of done this already if it was needed.
Not unless you tell them to and pay them to do it. Even then they probably wouldn’t do it. You do know that the holes aren’t tapped the whole way to the bottom during manufacturing of a stock block, right?
