What does everyone use for floor insulation , also is this for the heat or sound. How does the carpet fit after you install the insulation and any recommendations to use dynamat etc

The OEM tar was for acoustic damping.

Replace with Dynamat. It is a more effective acoustic solution than the OEM tar and weighs less too.

I used Klimat on my floors. Very happy with the results. I also found it very easy to apply adhesive to for laying down carpet on the longitudinals.

Click to view attachment

Yes, use the tar mats, not the foam sound deader. That can be used on back fire wall. Don't want anything on the floor that can soak up water.

Important clarification. Dynamat and Kilmat are Butyl. These are modern constrained layer damping materials. They are not tar or asphalt based.

There is a big difference in noise absorption between constrained layer butyl and the simple tar mats. OEM tar mats are available for those that want OEM / Concours finish. Constrained layer damping will outperform OEM tar by a wide margin.

if you have a bare newly installed floor or have scraped the old stuff off, just use the new reproduction floor pan tar kit. Six pieces that duplicate the original factory stuff. Stick heat and beat, then seam seal and paint the car's color

Thanks Superhawk996 for a great clarification. Mark

One thing that concerns me about the butyl is that it is very difficult to remove. Eventually, someone, someday, is probably going to have to remove it. Dry ice seems to be the best method but that involves beating on the floor with a small sledge and a chisel. The original tar wasn't that bad to remove with a heat gun and putty knife. Until I saw this thread I wasn't aware of the AA pieces. If they remove like the original then I'm leaning in that direction with the bonus that they are concours correct.

I removed all the tar but never bothered replacing it or putting anything else down. How much road noise do products like dynamite (or even the original tar) reduce? Worth the hassle & expense- especially given how noisy these cars are to begin with?

I went with U-pol tint-able truck bed liner. It will never absorb water and if you have no rust, seal it up. Did this on Taylor's car
Before and after

Tough as nails. Just needs to be a clean surface. Cleaned and applied acid etch primer as a base.

I put butyl sheets (Noico 80 mil butyl; Amazon) on the floors, and inside the doors. Coated almost everything (especially the non-butyl coated areas) with Second Skin Spectrum sound deadener. Road side of the floor pan was brush coated with Spectrum. All of the above will get bed liner sprayed onto it in a few weeks.

Dynamat.

Constrained layer mats reduce the noise a lot! IMO, they are a must unless you need to keep the car light. There are several brands of the constrained layer butyl. From what I saw, Dynamat outperforms the others but is also quite a bit more expensive. I used Noico which is slightly less effective than Dynamat but almost half the price. I painted mine so it looks OEM.

Exactly, how do we get so lucky to have an engineer on staff, and always willing to help to boot

Nice!
What did you use to paint under the sound insulation?

Mine are bare from doing the rail stiffening kit (after removing the old tar), and I wanted to know what's best to etch/prime/paint before putting the insulation down. I'm guessing seam sealer is needed too?

Not sure if this was directed at my post, but I used PPG DPLF epoxy primer before sticking the mat down. Then I etched the aluminum face on the mat with Ospho before spraying with DPLF reduced with acetone to use it as a flexible sealer. After that cured, I top coated with the same single stage used on the rest of the interior.

Here's where the sound deadening starts in my build thread