This is how the interior looked from when I pulled it out of the junkyard. Tired, ragged.

Below: An issue with the front seat caused me to need to retire it. I had a whole set of seats from my parts car that were in better condition and I had carpet purchased as a birthday gift sitting since 2007 waiting to be installed, so I moved ahead with pulling out the interior.

Below: Deconstruction starts. The Buicks had floorboard, layer of tar/felt material, under padding, foil backed insulation, and then the carpet.

Below: Nasty floor revealed. I did have a spot of rust through on the passenger front floor board right above the drain plug. Notice the metal vents in the front that bring warm air to the rear passengers. This stays hidden by the carpet and I thought this was a neat feature for 1964.

From the above picture to below, I've actually skipped a few years when I ran the car with no carpet, and just a rust converter floor and new seats. I needed a project to do on the car, and one day got the bug to put the carpet in it. Below is after I pulled the parts car seats back out, put some foil tape on the passenger side over my problem area, and put rust converter over the whole floor.

Below, the rust converter dries to a hard black.

First step I took to putting the carpet back in was laying tarpaper throughout the interior as it closely matched what the factory put in. I chose not to put in any foil backed insulation at this point. This view shows under the rear seat.

Here is a full shot of the carpet before installation. This was purchased for me as a gift and stored from 2007 to 2011. I specifically wanted carpet from Auto Custom Carpets, Inc, and I found a company called Auto Carpet Online that had the lowest price. In January 2007 the carpet was $158.03, the matching mats (always buy at the same time so the dye matches) were $48.83, shipping was a small $18.50, for a grand total of $225.36.

Installation started from the back per the instructions. The carpet was a bit off shade wise, with the original having more gold, but blends well with the original interior. I know it looks quite interesting with the red seats out of the parts car. 

Below: Before tackling the front carpet, the vents to the back were sanded and rust converter applied. Buick had the bottoms of these as plastic and the top as metal, likely so they would not deform under foot traffic.

Finished product.

Vents in place.

Tar paper on floor and hump.

The first piece of problem solving is the carpet didn't come up the kick panels. I had forgotten over the years there was padding in the front. I had to wait for a roll of jute backing to come from an eBay vendor before I could continue. In the picture are pieces I am cutting to shore up the difference in height.

Here was the second opportunity to problem solve. If you get two pictures down, the mats that shipped with the carpet were too wide and if the high beam switch was left in the factory spot it would have covered it. Rather than trying to get the mat cut, I was able to fabricate a bracket that moved the dimmer over about an inch using the original mounting holes.

Dimmer in place, jute ramps up to kickpanel.

Front carpet installed. Notice how dimmer is now almost centered in space between mat and kick panel and carpet meets kick panel.

Time to put in the front seat. I made cardboard templates from the bottom of the seat tracks to cut out just the amount of carpet necessary. Here it is shown with screwdrivers marking the initial location. Next I would cut the tracing with a knife.

All the front holes cut, including seat belt.

Job complete with seats in. Much quieter cruises after this! Notice the better condition door panels? See the next installment: replacing door panels.