55.2-59 Sound Deadener and Vintage Air

[57FleetsideC4]

Hi All, I am to the point on my 57 truck project that I am putting down sound deadener on the floor and firewall and have a couple questions. I am using Fat Mat on the floor and firewall up to the cowl and would like to know if this stuff will stick to the bottom of the cowl? I would also like to know if it is worth putting the 1/8" dynaliner on the firewall? My Vintage Air question is for anyone who has installed a Gen 4 system on 55-57 how tight of a fit is it behind the dash? They say to cut the original firewall pad where it bolts to the firewall. I don't have a the original pad in there just the .050 fatmat but if I put the 1/8" dynaliner there will it be to tight? Thank You Steve

[_Ogre]

i can't help you with either question, but have this tidbit to offer.
58TRUK has 2 layers of fatmat and a 1/8" layer of ensolite foam covering most of the interior. where my heel sits on the floor in relation to the gas pedal is a big divot. i suggest that you figure out where your heel will be on the floor, cut out the fatmat and foam and lay in a 6x6x¼ piece of hard rubber. i've always had a floor mat in truk and only notice the divot when i vacuum, but you can tell that the carpet is sitting on the metal floor, the fatmat is mushed up on the sides.

[mr48chev]

I don't think that you will have an issue as the fatmat will compress pretty flat. You could take a small scrap piece and squish it between two pieces of metal with the same pressure you would put on the bolts that hold the Vintage air system in place and about the same square inches and then measure it to have peace of mind though.

The original cardboard and fiber material firewall covers don't compress well and a 70 year old original would probably fall apart if you tried to compress it. Meaning you never get a solid mount with it between the firewall and anything you are trying to bolt to the firewall.

Up under the top of the cowl industrial grade contact cement is probably your best go there.

[leegreen]

I used a similar product from a different brand on the roof with no issues. Black paint in the sun for one season so far with no signs of the bond failing. It may get hotter where you are.
Fatmat has a gallery that shows the stuff on roofs.

I did not do the top of the cowl as I put the sound deadener in towards the end of the build. In hindsight it would be better to do the firewall and underside of the cowl after paint, before fitting pedals, column and wiring.

[57FleetsideC4]

Thanks for the comments guys. I have decided one layer of fat mat will be enough for me (I have to stop overthinking this stuff). If it's a little loud so be it. I may try to put some fat mat on the cowl before starting to put this truck together. Steve