440 wrist pin noise?

Exhaust leak for sure.
As the manifold heats up the crack grows and the noise get worse. When you put it in gear the rpm drops, the exhaust cools off and the crack shrinks. When you take off, the exhaust heats up. The harder you press the gas, the faster it heats up.
Temperature at the port exit can vary from 200 to 400 at idle and hit 600 pretty quick.
A bad wrist pin can be found much like a bad rod. Just pull the plug wires off one atta time. When you find the right one, the noise quietens right down.
A bad wrist pin is a rhythmic; tictic---tictic---tictic---tictic