Exterior three-quarter view of Brandon's 1981 Dodge B350 with HornBlasters Flatlaw 3 Liter train horn kit featured customer install gallery photo 1

Close-up of Flatlaw 3 Liter train horn on 1981 Dodge B350 HornBlasters gallery photo 3

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Featured Install

Flatlaw 3 Liter Train Horn Kit

Brandon's 1981 Dodge B350

Sound Sample

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Owner Brandon

Year 1981

Vehicle 1981 Dodge B350

Brandon J. gave his 1981 Dodge B350 van a serious upgrade by installing the HornBlasters Flatlaw 3-Liter Train Horn Kit, bringing modern volume to this classic ride. The compact Flatlaw kit fits snugly into the B350’s vintage chassis, making it one of the cleanest sleeper installs we’ve seen on a retro van.

Don’t let the size fool you, this small kit delivers massive sound, turning heads and shaking streets wherever Brandon takes it. It’s the perfect fusion of old-school character and new-school noise.

Whether you're a vintage van lover or just want something loud in a compact form, Brandon's setup proves that classic vehicles can still bring the heat, and the honk.

Feature Highlights

Flatlaw low-profile horn assembly designed for tight mounting locations
3-liter integrated tank and compressor operating at 120 PSI
Approximately 2-minute fill time with 35-second recovery
Complete wiring and relay kit for quick installation
Perfect stealth upgrade for classic vans like the 1981 Dodge B350

HornBlasters Shocker S6 544K Nightmare Edition Train Horn Kit

PRODUCT

PRICE

Sold out

UP TO 1500% LOUDER

UNLIMITED HONKING

ZERO
DELAY

CAPABLE ONBOARD AIR SYSTEM

STEALTH SOUND, MAXIMUM IMPACT

Give your classic ride a modern voice with the Flatlaw 3-Liter Train Horn Kit, just like Brandon’s Dodge B350. It keeps the van’s lines clean while delivering a powerful horn blast that makes sure you are heard the moment you roll in.

SPECIFICATIONS

Part Number	HK-F3B-M3
Horn	Flatlaw train horn
Horn Length	17.5" (444.5 mm)
Horn Width	16.25" (412.75 mm)
Horn Height	8" (203.2 mm)
Horn Weight	12.5lbs (5.67 kg)
Voltage	12-Volts DC

Air Source Kit	3-Liter air compressor & tank combo
Operating Pressure	120 PSI
Restart Pressure	90 PSI
Air Source Length	16.535" (420mm)
Air Source Width	4.921" (125mm)
Air Source Height	7.086" (180mm)

FILL RATES

3-LITER AIR TANK	FILL RATE
0 to 120 PSI	2 min. (± 10 sec.)
90 to 120 PSI	35 sec. (± 05 sec.)

Flatlaw 3-Liter Train Horn FAQ

The Flatlaw 3-Liter Train Horn includes the low-profile Flatlaw horn assembly, a 3-liter (0.79-gallon) air tank with integrated compressor, a 120 PSI pressure switch (90 PSI restart), wiring harness, relay, airline, and mounting hardware. Brandon fit the entire system inside his 1981 Dodge B350 without sacrificing cargo space.

Despite its compact footprint, the Flatlaw produces a powerful, deep train horn tone that greatly outperforms factory vehicle horns. It delivers true train horn authority while remaining discreet under the vehicle.

The integrated 12-volt compressor draws up to 20 amps and fills the 3-liter tank from 0 to 120 PSI in roughly 2 minutes (±10 seconds). Recovery from 90 to 120 PSI takes about 35 seconds, allowing repeated horn use.

The Flatlaw system is primarily designed for horn operation, but it can supply short bursts of air for light-duty tasks such as inflating small tires or clearing debris. For extended air tool use, a larger onboard air system is recommended.

The Flatlaw's ultra-low-profile, all-in-one design makes it ideal for vintage vans where space is limited. Brandon preserved the clean interior of his Dodge B350 while gaining a horn system up to 1500% louder than stock.