Jerry Heasley
December 26, 2014

Our ’68 Mustang convertible project is now running (see Oct. ’14 Mustang Monthly) and we’ve got new brake hardware coming for a future installment of our mechanical needs to get the convertible on the road. While we’re waiting on the brake parts and a few other items we decided to install a new convertible top, as the car had no top at all on it when purchased.

We could have simply picked OEM vinyl for the top, but then we heard about a new “acoustic” top material with the look of a cloth “Stayfast” material, but made out of vinyl. This acoustic top is constructed with a heavier backing to absorb road noise better than regular vinyl, yet looks like a more expensive twill cloth top. The price of the acoustic top option wasn’t any higher than OEM vinyl, so I chose this new material.

The brand name is Trilogy Acoustic Vinyl and we ordered our top from Robbins Auto Top. They have all of the popular colors for pretty much every Mustang ever built, from ’64½ to the present. The Trilogy Acoustic Vinyl material is a heavy-weight 45-ounce two-ply composite material that has the look of more expensive German cloth tops found on high-end cars, yet is up to 20 percent quieter in reducing road noise. While not 100 percent correct in appearance, if you’re building a driver or restomod and want to enjoy a quieter and more comfortable ride, the Trilogy Acoustic Vinyl top is obviously your best option.

1. Troy Anderson and his wife Christy hold up Robbins Auto Top’s new Trilogy Acoustic Vinyl top, so named for the heavier polyester backing that absorbs road noise better than OEM vinyl tops.

2. Troy first stapled into place “bow pads” lengthwise on either side to hold the top bows in place. Notice how he also has stretched tape (yellow color) between the bows to position them. Once in place the bow pad’s ends were trimmed of excess material using scissors and cauterized with an open flame to prevent fraying.

3. Troy pre-fits the acoustic top to the frame. Pre-fitting is a starting point to align the top with the bows underneath.

4. This fabric lip staples to the rear bow to keep the top from ballooning when driving.

5. One critical check on top fit is lining up the indentation in the top material (at the end of the bow’s outside molding mounting point) to the top side rear quarter reinforcement in the top bow.

6. According to Troy’s shop manual, the rear top bow to the chrome trim strip in the rear body should measure 20.5 inches. This is the “bow height” for the rear bow and will determine the top frame’s location in regards to the top material.

7. Next, Troy and Christy pre-fit the rear curtain. Robbins marks each rear curtain with a center point. After measuring the rear bow, Troy determined the mid-point and lined the two chalk marks for installation. You can order your rear window in either 40-gauge plastic or with a two-piece glass panel. We picked the smaller glass curtain, which folds as the top is lowered.

8. Confident of good alignment, Troy staples the rear curtain to the rear top bow.

9. This rear tack strip screws to the inside of the back of the convertible top well

10. First, Troy staples the fabric of the rear curtain to the inner part of the rear tack strip.

11. Using scissors, Troy cut out openings around the holes in the rear tack strip. Metal screws will secure this tack strip, through these holes, to the inside of the back of the convertible top well.

12. Likewise, curved tack strips secure the sail panels of the convertible top on both sides. Robbins supplies the white chalk mark as a starting point for fit, as seen here.

13. Staple the fabric top in place and cut out openings to expose the holes in the tack strip. Screws go through these holes to anchor the top to the inside corners of the convertible top well.

14. Troy inserted the screws to secure the sail panels and all around the inside of the convertible top well.

15. Troy stretches taut the convertible top over the frame and then clamps the top to the forward edge of the top frame. Spray glue is applied to secure the top at the front of the frame.

16. Troy sewed the convertible top bead (white) into a strip of convertible top material, both supplied with the kit.

17. Troy stapled the sewed strip of material, with bead sewed inside, to the inside front edge of the convertible top. The bead provides a cushion that helps create a snug fit of the top to the windshield header.

18. Next, staple the outside top molding to the rear header bow to secure the convertible top.

19. Finally, install the chrome end caps, one on either side of the top molding to finish the rear header bow molding.

20. Troy laid a piece of cloth top material across the new Trilogy Acoustic Vinyl top for comparison. Robbins said the new acoustic top is vinyl in construction, but uses a roller of twill weaves in the manufacturing process. In other words, the roller that prints the pattern into the fabric is engraved to mimic the twill weave of the more expensive German cloth materials.

Additional Sources

(806) 367-9612