I got to know Mac while machining parts to fix Nine 0 Nine's bomb bay doors... he had flown for the Collings for 20 years and was the highest time
B17 pilot in the USA with over 7,300 hours... He was also the Safety Officer for the foundation...

If Mac rolled on a engine that didn't pass mag check then even he would call negligence... if Mac rolled on a engine that passed mag check then why wouldn't he expect full power???