Finally, my first 360 and goals for it! I'll be asking a lot of questions.

Your machinist must not do performance very often. Years ago I had a machinist say the same thing, he went blah blah blah and I said do it anyway. He did it and put on the receipt really big "cut .040 at customer request" and I had to sign it. LOL..... That project was about 20 years ago and those 360 heads are still on that 318 (I know the guy I sold that Dart to) and runs fine.