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From Ratty To Natty: Pt 2

Further Adventures In Replacing An Early C4 Interior

John Nelson May 22, 2003

Make no mistake about it--the sight of one's very own Corvette, sans interior and essentially gutted, can be a bit disconcerting. That's where we left off last month, as we took on the challenge of performing a do-it-yourself interior replacement on an early C4. Now, it's just common sense that the old has to come out before the new can go in, right? Even so, the sight of my interior-less Corvette, and the knowledge that I was responsible for putting things right again, brought on a grave case of the "I should'ves." As in, "I should've had someone else do this!" On the positive side, things took a definite upward turn as we began to put our subject (victim?) '84 back together again.

Much of the positive outlook came about as we actually begin to fit the replacement interior pieces into the car. The main reason for the change of attitude is that the new parts fit--and fit well. The plastic parts were either GM replacements or exact reproductions.

When it came to the seats, the bulk of the work was done for us (see sidebar). In fact, except for some minor carpet trimming and gluing, this was truly a remove and replace process. This amazed one of my colleagues (and helpers), Street Rodder staffer Jason Walker. Jason's experience with street rods has taught him that aftermarket parts usually don't fit without being modified. In the Corvette aftermarket, however, suppliers such as Corvette Central know how exacting the Corvette owners are, and this attention to detail certainly benefits the home mechanic.

So, we start Part Two with a dismantled Corvette and a bunch of new parts that fit correctly. Before reassembling our barren C4, however, we decided to address an issue that many early C4 owners know quite well--noise. I didn't nickname my '84 "The Bronze Bomber" for nothing-- this is one noisy car. Our tests with a decibel meter bore this out, as we got interior sound level readings from 90-104 dB at speeds ranging from idle to 70 mph. That's much too noisy, and we turned to Scoche Industries for help. Scoche's Accumat is designed to block out or dampen unwanted noise, depending on the thickness of the material. We used AMT250, a 1/4-inch sound-blocking material, on the hatch floor, behind the seats, and on the floorpans. We also used AMT045, a .045-inch thick sound damping material, on the rear wheelwells and along the transmission tunnel. Both types of Accumat are easy to use. Once the material is cut to size, it sticks to the car with an adhesive backing and can be molded to the sheetmetal. Will it work? And will it help block out the dreaded C4 drone? We'll let you know in Part Three, when the car is finally put back together and we can perform an "after" test with our decibel meter.

So, with a new layer of sound control material lining our C4's cockpit, it's time to start putting the new interior pieces into place. As we said, everything fit really well. If you pay attention to how the old parts came out, putting the new ones in is not difficult. One thing that we didn't do, however, is keep very good track of all those little screws that hold so many of the plastic panels in. You, of course, will do a much better job of bagging and tagging all those little bits and pieces. In our case, a quick phone call helped save us. C Central sells an Interior Fastener Kit, which even comes with an index sheet that says which screws go where--believe us, this kit was very handy, also ensured that we had new screws to use in visible areas.

Other than that, there ain't nothing to it but to do it. Take your time, as we did, and work deliberately. Our goal here is twofold--we want everything to look good, and we also want it to work correctly. As we continue through Part Two and finish up in Part Three, both of these goals are within reach, and we're looking forward to having a Corvette interior we can enjoy and be proud of.


At the end of this installment, our guinea pig C4 will have a layer of brand-spanking-new carpet, and we'll be ready to bolt everything back together in Part Three. Follow along to see how we got there.

We decided to line our '84's inner floor panels with Accumat in an attempt to quiet the "Bomber's" roar.

In this shot, we've lined everything with the sound-blocking material, and Jason is lining the rear wall with the thinner sound dampening material.

We also covered the wheelwells... well as the transmission tunnel and the floorpans. Next month, we'll let you know if we succeeded in making things a bit quieter.

After finishing with the Accumat and reinstalling the factory insulation pieces, we test-fitted the seat back carpet section. Note that it's much too long as is, covering part of the compartment doors. Removing the doors and their frame as a unit makes it easier to fit the carpet.

To make this section the proper size, we put the carpet in place, marked a cut line on the backing material, and used a sharp knife to cut off the excess. Note that the carpet must be molded around the "ridge" of the hatch area. Our cut was just about perfect. We also went ahead and threw some Accumat into the storage compartment. It can't hurt, right?

With the compartment doorframe back in place, we used an awl to punch holes for the frame screws.

Voila! We've got our first piece of new carpet in the car. Things are looking up!

We then turned our attention to the wheelwells. These pieces are molded into the proper contours, and just need to be worked into place. Start with tucking the carpet into its groove. We left the rear window side panels on; the job's probably easier with them off.

The wheelwell carpet comes with a notch for the top holders, but this opening will need to be carefully enlarged to fit properly.

We've now got wheelwell carpet. Note the holes for the stereo grille mounting holes (arrows). Along with the contours and the top holder notch, these help locate the carpet.

It's now time to install our new hatch floor carpet. This piece runs up the back of the hatch area. We had already clicked our new rear curtain into place, so the carpet had to be slid underneath it... which point we discovered that this section also needs to be trimmed. We turned the new piece face down on a clean table, laid the old piece on top of it, and made the necessary cut.

After firmly pressing the carpet into place (see the lead photo), we were looking good and were ready to reinstall the storage compartment locks.

The locks are reinstalled in the reverse of disassembly.

Using the compartment door handle as a template, you'll need to cut a small hole for the mounting screw. With that, our "back room" is carpeted!

Moving forward, we next tackled the console strips.

We'll be reusing the plastic pieces, but that old carpet has to go. Applying a little muscle, we ripped it right off.

First, we thoroughly cleaned the plastic panels. After using the panel to trace a pattern onto the back of the carpet and masking off the "cosmetic" areas, we sprayed a coat of 3M Hi-Strength 90 Spray Adhesive onto both the panel and the carpet. After letting it dry for a minute, we carefully joined the pieces together, using the angle in the pieces as a locating point.

While the console strip pieces were drying, we replaced the factory insulation from the passenger compartment and installed the floor carpet. These pieces feature a factory-style "mass back" backing and are molded to fit.

The carpet will need to be tucked in behind the seatbelt housings.

Yes, it's that easy! The hardest part is cutting holes for the seat mounting bolts. We made sure the carpet was in place, found each bolt, and cut a small "X" right over it. The bolts popped right through.

Continuing on, Ryan flipped the now-dry console strips over and used our awl to poke holes for the mounting screws.

He then moved the much nicer looking strip into place. The driverside piece needs to be slid behind the driver's heel pad... seen here. The mounting screws located in the plastic and along the top of the strip are easy to find; those that go through the carpet are a bit more trying, but the holes we made helped.

Finally, the carpet installation is completed by installing the driver's and passenger's dash pieces. Both the dash and the carpet back were coated with our spray adhesive. Ryan left the edges bare, making it easier to slide the pieces into place. The dash pieces and the mounting screws will hold the edges in place.

Ryan then carefully pressed the dash pieces into place making sure everything fits well.

After gluing in the pieces on both sides, the plastic under-dash panels can be reattached. At this point, our subject '84 has left "ratty" behind and is more than halfway to "natty." Join us next time as we put this C4 back together and dress it up with a few extras. Ciao!


One of the hardest parts of replacing any car's interior has got to be dealing with the seats. Going through the process of hog ringing the covers to the foam before installing the new pieces into our C4's seat buckets was not something I was looking forward to. As it turned out, however, I didn't have to do it at all. Corvette Central's Scott Kohn suggested that I opt for Mounted Standard Seat Covers. Here's the deal: My new leather seat covers, already attached to new foam and ready to install, were priced at $1,009, plus tax. The separate pieces (Leather Standard Seat Covers, Standard Seat Foam, a Seat Cover Installation Kit, and Hog Ring Pliers) come in at $1,016.95, again plus tax. It actually costs less money to get everything preassembled, and it saves some work, to boot. If you take the pieces to an upholstery shop, it costs even more. We'll show you a bit of what's involved if you want to re-cover your old foam, but it's hard to beat the convenience of ready-to-install seat cushions.


Corvette Central
Sawyer, MI 49125
Scoche Industries
Oxnard, CA 93033



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