I haven't checked what's in my hood, but you may be right to avoid felt. It would tend to retain moisture and promote rust, unless it was impregnated with oil or tar. My hood isn't really very accessible right now, but I can try and check.
In my cab at the center top between inner and outer rear panels was a piece of rubber foam material, serving essentially the same purpose of reducing vibration.
Your link doesn't say how thick that sound deadening material is.
Last edited by klhansen; Sun Aug 02 2020 07:16 PM.
First car '29 Ford Special Coupe
#2 - '29 Ford pickup restored from the ground up.
Newest Project - 51 Chevy 3100 work truck. Photos
Busting rust since the mid-60's