START HERE - To the right you see 2 pictures when I have put some stuff on to help with heat, and sound issues. MOST folks buy stuff like DynaMat or similar items to do this step with. Through my research and with help of some guys at different Street Rod forums I found out you can get just as good a result with only about 20% of the cost. Last I checked DynaMat cost bout $230 for 36 square feet. (that's almost $6.50 a square foot) What I used is called Peel & Seal. People I spoke with swear it is just as good as DynaMat. It can be found at Lowes, comes in a 25 foot roll, and is six inches wide. It only cost about $1 per square foot. Since it's so cheap I plan on applying two layers most places. This will also help with the hollow sound you get from the doors and other voids. Makes it much nicer acoustically.
Now something else. Many folks also use something called "Lizard Skin" It's a product you spray or brush on to dampen vibration, cut down on noise, and help reduce heat. You can't see under what I have applied, but I used another product that works the SAME, but is much cheaper than Lizard Skin. I'll explain below.