insulated interior
we had a heat wave in NorCal last month and everything inside the truck was hot - 125F (plastic bits) and 135+F (metal bits) just driving on hwy - ambient was around 110F. So, decided to insulate the cab. Bought about 100sqft of heat insulation from amazon ($70) and wrapped most of the horizontal surfaces of the truck.
Weather has cooled off since, but after 90min hwy driving, I was seeing between 10F difference metal floor panel with & without insulation, and in battery box (panel closest to frame&muffler), about 30F surface temp differences between painted metal (130F) and insulation (95F, IIRC) on the same panel/face. So, I'll wrap the rest of the battery box.
I plan to put the HAM radio inside the center console box...and that inside was was an oven. Hopefully, multiple layers of this down the center will keep things cool enough not to fry the radio.
The heat barrier seem to work pretty well, IMO. This Insulation is not as expensive as some other top-brand thermo shields/barriers out there. So, I didn't have high expectations... esp. when truck is all metal, cats & muffler are inches from frame and panels, no heat shield, whole thing not air tight, carpet is made of burlap with vinyl covering.
And it does require spray adhesive, but for the money and time spent taking things apart... I think it was worth it. Some carpets sticks out a bit b/c the insulation is thicker,... but no one really notices anyways.
Here is the product.
https://www.amazon.com/gp/product/B00PX2C8DC/
I used the 3M Super90 (?) spray adhesive. Took a couple days to wrap the inside.