[Capri306]

Coolant lines pass through the EGR spacer on a 5.0L to keep that area's temperatures under control, as well as a Michigan-proofing. I've seen people block them off, and it's okay on an application where EGR is disabled. However, the intake temperature will skyrocket without the coolant flowing through if it is working as designed.

Seriously, I don't think this will do $hit for any more power or fuel economy. At the rate the air is flowing past the throttle body, just how much heat do you think is being transferred to the intake charge? At wide open throttle, most of the air is not contacting the throttle body's bore, either. Come on, let's be realistic. Even in the days of carburetors, that heat stove on the exhaust manifolds could hardly get the intake stream above ~150F. Even at a lower temperature, the air would be warmed up by the time it gets to the plenum and runners from ordinary engine heat.