Aluminum or Cast Iron Intake?

I'm researching the build for my upcoming 460 MPG/Torque rebuild. Here's the question I'm asking. Should I go with the stock cast iron intake or should I go with an aluminum intake? I know about the weight savings with aluminum but I also am looking at how aluminum is a heat soaker as well. So what do you'll think? I'll give you'll a little taste of what I'm doing here. This rebuild is for my 85 F350 dually that I use to haul my race car to the track. My goal with this engine is to build a motor that will get good torque to tow my car & trailer up & down many mountains on the interstate but also get maximum gas mileage for this engine. I also want to be able to take long trips on the interstate as well ,even when not towing.