440 power gains/ aluminum head advantages?

The 60 foot and lack of pull from cruise (flash rpm wasn't mentioned) seems to point to the converter. I guess high trans temp would be a sign during cruising. Fuel supply can be ruled out in my opinion because full float bowls should get you out past 60 feet. Timing is certainly a good possibility. The damper timing mark should be verified to be accurate at TDC, and degree the cam for sure.