Over heating 66 Dart

Yes, the engine was taken to a machine shop and it was put in acid, the deck was cut 5 thousand the heads were cut 5 thousand, the rods checked and the crank was polished. Plus when we got the block home we washed it out with soap and water, used brushed to clean out all the galleys and put in the new freeze plugs. My brother done the assembly of the enging and he is ASE certified master mechanic. But he is retired and lives in Florida, so I don't have his help in person. We talk on the phone, but so far we can't seem to narrow down the issue. Thank's