A Peterbilt 377 hood conversion can mean several different things. You may simply be replacing a damaged 377 hood. You might be trying to determine whether a 377B or Peterbilt 385 hood will fit your truck. Or you may be planning a more extensive conversion to a 378- or 379-style front end. Those are very different projects.
Before ordering a hood, the safest approach is to identify the truck configuration, measure the existing hood and check the mounting, headlight and air-intake setup. A hood advertised for a “Peterbilt 377” is not automatically correct for every 377.
If you're starting with a standard 377, you can also browse the available Peterbilt 377 parts and replacement hoods while comparing the fitment details below.
Peterbilt 377 vs. 377B vs. 385 Hood Fitment
One of the biggest sources of confusion is the relationship between the Peterbilt 377, 377B and 385.
Aftermarket catalogs distinguish the regular 377 hood from the later 377B/385 Long design. The standard Peterbilt 377 set-back-axle replacement hood is listed at 55 3/4 inches at the centerline. By comparison, the shared 377B/385 Long hood is listed at 62 1/2 inches.
| Configuration | Common aftermarket identification | Important fitment clues |
|---|---|---|
| Peterbilt 377 SBA | Approximately 55 3/4" centerline | Standard 377 configuration; check build date, axle position and headlights |
| Peterbilt 377B / 385 Long | 62 1/2" centerline; commonly listed for 1998–2007 applications | Air intakes on both sides; split-fender design with cab-side fender extensions |
| Peterbilt 385 Short | Separate 51 3/4" hood design | Left-side air intake; not interchangeable with the 377B/385 Long hood |
Big Truck Hoods carries a dedicated Peterbilt 377B and 385 Long parts collection, which is useful because these applications share certain components while remaining distinct from the standard 377.
That makes the model name only the beginning of the fitment process.
What to Check Before Ordering a Peterbilt 377 Hood
Start with the truck itself rather than an online product photo. Confirm the model and build year, but also determine whether the truck has a set-back axle or set-forward axle.
Next, measure the hood centerline. This is normally measured down the center of the hood from the rear edge near the windshield to the nose at the grille. Hood length and BBC can also vary considerably between closely related Peterbilt models. For another example, see our guide to Peterbilt 388 vs. 389 hood length, BBC and exterior differences.
The OEM number is another valuable check. The standard Peterbilt 377 replacement offered by Big Truck Hoods references OEM numbers including 13-04231, 13-04564A101 and 13-04230UNF.
For the 377B/385 Long configuration, the Peterbilt 377B / 385L replacement hood lists OEM references including 13-04614UNF, 13-04614, 13-04670, 13-04704 and 13-04760. Air-intake location can also help identify the correct hood. The 377B/385 Long design uses air intakes on both sides, while other 385 configurations use a different setup.
Don't Assume Your Existing Headlights Will Transfer
Headlights are one of the details most likely to complicate a Peterbilt 377 hood replacement. Depending on the truck's year and the replacement hood, the original headlight configuration may not transfer directly. Replacement bezels, shims or other mounting hardware may be required.
For example, the standard 377 replacement listing notes that trucks from 1991 or earlier may require updated headlamp bezels. It also identifies several OEM shim options that may be needed around the hinge or rear roller bracket.
That means a hood shell alone may not be the complete conversion. Before removing the old hood, compare the headlight openings, bezels, mounting brackets and adjusters between the existing hood and the replacement.
Check the Hood Hinges and Rear Locators
Hood length is only part of fitment. You also need the hood to sit correctly at the front hinges and locate properly against the cab when closed.
This is especially important with the 377B/385 Long design. Big Truck Hoods notes that some earlier applications use old-style locator brackets that cannot be reused with its replacement hood. Later-style roller locator brackets are required for those trucks.
The standard 377 replacement may also require shims around the hinge or rear roller bracket to achieve correct alignment. This is why two hoods with a similar exterior shape can still require different installation hardware.
What Parts Might Be Needed for a Peterbilt 377 Hood Conversion?
Think of the conversion as a front-end assembly rather than just a fiberglass shell.
Depending on the truck and replacement hood, you may need to transfer or replace:
- Grille and grille surround
- Headlights and bezels
- Hood hinges
- Hinge hardware
- Rear roller or locator brackets
- Hood latches
- Fender extensions
- Air-intake components
- Bumper or associated mounting hardware
The 377B/385 Long collection includes compatible grille and grille-trim options alongside the hood itself, which can make it easier to identify related front-end components for that configuration.
Checking these pieces before ordering the hood can prevent a situation where the new shell arrives but the truck still cannot be assembled.
Does a Peterbilt 385 Hood Fit a 377?
Sometimes - but “385 hood fits a 377” is too broad to use as a fitment rule. The important overlap is between certain 377B and 385 Long applications. A shared replacement hood is available for those configurations, but that does not mean every 385 hood fits every 377.
The Peterbilt 385 Short replacement hood, for example, has a 51 3/4-inch centerline measurement and a left-side air intake. It is a separate design from the 62 1/2-inch 377B/385 Long hood.
For an original-style 377, verify the existing hood measurement, axle configuration and OEM number instead of ordering a 385 hood based solely on the model name.
Can You Put a Peterbilt 378 or 379 Hood on a 377?
This is where “hood replacement” becomes a true conversion. Owners have completed 377-to-378 and 377-to-379-style conversions, but these should not be considered normal bolt-on replacement procedures.
Changing to another hood style can affect the hinge mounting points, bumper position, axle clearance, radiator clearance and cab-to-hood alignment. Additional brackets or fabrication may be required. If the goal is a 378- or 379-style appearance, compare the complete front-end geometry before purchasing the hood.
For standard replacement options across these models, the broader Peterbilt truck parts and hood collection can also help you compare the available applications.
Always Dry-Fit a Fiberglass Hood Before Painting
A replacement fiberglass hood should be fitted to the truck before final paint.
Big Truck Hoods specifically instructs customers to inspect and test-fit parts before painting and notes that modification may be necessary before final assembly.
During the dry fit, check:
- Hood-to-cab gap
- Grille position
- Fender-to-tire clearance
- Headlight alignment
- Hinge movement
- Rear locators
- Hood latches
Only once those points are correct should the hood move into final bodywork and paint.
For more information about maintaining the material after installation, see the guide to fiberglass semi-truck hood care and maintenance.
Final Fitment Checklist
Before purchasing a Peterbilt 377 replacement or conversion hood, verify the truck's:
- Exact model and build year
- SBA versus SFA configuration
- BBC specification
- Hood centerline measurement
- OEM hood number
- Air-intake locations
- Headlight and bezel style
- Hinge hardware
- Rear locator brackets
- Required fender extensions
Doing those checks before ordering is much easier than trying to make the wrong fiberglass hood fit after it arrives.
If you need a replacement, browse Peterbilt 377 parts or the Peterbilt 377B / 385 Long collection to compare the available hoods and related front-end components.