I wanted to update this thread for anyone searching for DIY intakes and heatshields. I used this cardboard and tape to mock up the shape I wanted my heatshield to be.

I then flattened this cardboard template to trace an outline on some aluminum from Lowes. Cut it out with come tin snips, and added this trim to the bottom and front https://www.amazon.com/MATCC-Protect..._1519579052038
I used this on the top and rear edges to tighten fitment against the fender wall and the hood https://www.amazon.com/dp/B019RXHYVS...detail_5?psc=1

My theory was to try and seal it from the back side of the factory intake duct (which I left to keep cooler air flowing to my filter), to my intake pipe. I slightly angled the top of the aluminum heat shield, so the hood bends the shield just slightly towards the engine. I figured this, plus the form filling abilities of the bulb trim on the top would keep it as air tight as possible, over those headers. It definitely does make a difference in delaying high IAT's, but if you are in traffic on a hot day, or doing multiple pulls- IAT's still get hot.

Used 2 self tapping screws with 1 rubber and 1 metal washer each, to attach. Here is the finished product: