Sorry, another oft' used, and almost completely specious, red herring.

Given the surface area and wall temp and induction flow rate, even on a N/A engine the heat transfer in inlet tract is not significant.

The only significance of heatsoak is either at idle/slow trickling with the air intake in 'dead space' in the engine bay that becomes/stays a hot spot. Many people don't understand under bonnet air flow and don't allow for the effects of the air intake actually having a major influence more significant than any imagined 'ram' effect from vents/ducts.

Martin