Overview
Building a rat rod? Chopped the top? Deleted your vent windows? If you've modified your classic car or truck beyond factory specifications, you've probably discovered that vehicle-specific weatherstrip kits won't fit your custom bodywork.
Good news: Metro Moulded Parts offers a wide selection of universal extrusions sold by the foot that let you seal virtually any custom opening—you just need to know how to measure and select the right profile.
Why Vehicle-Specific Kits Won't Work for Custom Builds
Metro manufactures weatherstripping for thousands of classic American vehicles from the 1940s–1990s. Our kits are engineered to match original factory specifications. When you modify your vehicle, those specs no longer apply:
- Chopped tops change windshield and rear glass dimensions
- Vent window deletes require different glass run channels
- Custom fenders may need non-standard welt or edge trim
- Suicide door conversions alter door opening geometry
- Sectioned bodies change trunk and door frame perimeters
We cannot manufacture one-off custom seals (tooling costs exceed $10,000+). Instead, we offer universal extrusions that let you create your own custom seals.
Universal Extrusion Options at Metro Moulded Parts
We stock numerous profiles sold by the foot, allowing you to buy exactly what you need:
| Profile Type | Common Part Numbers | Best Used For |
|---|---|---|
| "U" Channel | LP 17-B, LP 23-C | Edge protection, glass channels, body seams |
| Door Side Seal | LP 60, LP 70 | Custom door openings, suicide doors |
| Glass Setting Rubber | LP 102-E | Windshield, rear glass (rope-in method) |
| Door Bottom Seal | LP 104-B | Custom door bottoms, cargo areas |
| Side Window Seal | LP 95 | Roll-up windows, custom quarter glass |
| Square Extrusion | Various 3/4" profiles | Trunk lids, hatch seals, compartments |
How to Measure for Universal Extrusion
Step 1: Measure the Perimeter
Using a flexible tape measure or string, trace the entire perimeter of the opening you need to seal. Add 2–3 inches for overlap at the splice point.
Example: A custom trunk opening that measures 96" around = Order at least 99" (8.25 feet)
Step 2: Measure the Channel Gap
For "U" channel applications, measure the thickness of the material you're sealing around:
- 1/8" to 3/16" = Small U-channel
- 1/4" to 5/16" = Medium U-channel
- 3/8" and larger = Large U-channel or bulb seal
Step 3: Determine Compression Needs
Consider how much the seal needs to compress when the door/trunk/window closes:
- Light compression = Dense rubber extrusions
- Heavy compression = Sponge rubber or hollow profiles
Vent Window Delete Applications
One of the most common custom modifications we're asked about is the vent window delete—replacing small triangular vent windows with a single pane of glass.
What you'll need:
- Glass Run Channel – New continuous channel to replace the segmented OEM channel
- Beltline Weatherstrip – Modified or universal inner/outer sweeps
- Division Bar Seal – May no longer be needed (remove entirely)
Since we don't manufacture vent window delete-specific kits, use our universal Glass Setting Rubber (LP 102-E) and glass run channel extrusions cut to your custom length.
Installation Tips for Custom Applications
- Dry-fit everything first Before applying any adhesive, do a complete test fit to identify problem areas.
- Use quality adhesive Universal extrusions rely entirely on adhesive (no factory clips). 3M Black Weatherstrip Adhesive (GL-11) is the industry standard.
- Plan your splice location Place splices in low-visibility areas (bottom of door jamb, under trim). Cut ends at matching 45° angles for invisible joints.
- Allow break-in time New SUPERsoft rubber needs time to conform to your custom openings. Expect doors to close firmly for the first week before the rubber "memorizes" the compressed shape.
- Protect your investment Wear Nitrile Gloves (GL-10) when handling adhesives, and use our 7-Piece Trim & Pry Tool Set (GL-30) to avoid damaging paint.
When to Call Us
If you're unsure which profile matches your application, contact our sales team with:
- Photos of the opening you need to seal
- Measurements (perimeter length + channel gap width)
- Description of your modification
We can help identify the closest universal profile or suggest alternatives from our catalog.