S24A 341 Adventurer
1956320 hp @ 5200 rpm
Dual-quad high-performance launch version
DeSoto 341 Hemi enginePhoto: Joe Ross · CC BY-SA 2.0
DeSoto · FireDome / FireFlite / Adventurer Hemi
DeSoto 341 Hemi
The enlarged DeSoto Hemi that powered both regular 1957 models and the 320-hp 1956 Adventurer.
341
Cubic inches
The 341 became DeSoto's first serious one-horsepower-per-cubic-inch-era performance engine when the 1956 Adventurer received dual quads, higher compression and larger valves.
Key variants
All variantsS24A 341 AdventurerS25 341 FiredomeS26 341 Fireflite
Displacement
341 ci
Bore
3.78"
Stroke
3.8"
Years
1956–1957
Key Takeaway
The 341 paired a 3.78-inch bore with the 3.80-inch tall-deck stroke and, in Adventurer form, added dual four-barrels, higher compression, larger valves, and performance calibration. It was DeSoto's first Hemi developed as a true halo engine.
Technical Specifications
- Compression
- 9.25:1
- Horsepower
- 320 hp @ 5200 rpm in 1956 Adventurer; 270 hp @ 4600 rpm 1957 Firedome; 295 hp @ 4600 rpm 1957 Fireflite / Firedome Power Pack
- Torque
- 356 lb-ft @ 4000 rpm in 1956 Adventurer; 350 lb-ft @ 2400 rpm 1957 Firedome; 390 lb-ft @ 2400 rpm 1957 Fireflite / Power Pack
- Architecture
- 90-degree OHV Hemi V8
- Block
- Cast iron
- Cylinder heads
- Cast iron
- Valvetrain
- Pushrod OHV with dual rocker shafts
- Aspiration
- Naturally aspirated
- Fuel delivery
- Carbureted; dual four-barrel induction in Adventurer trim
- Firing order
- 1-8-4-3-6-5-7-2
- Main bearings
- 5
The 341 paired a 3.78-inch bore with the 3.80-inch tall-deck stroke and, in Adventurer form, added dual four-barrels, higher compression, larger valves, and performance calibration. It was DeSoto's first Hemi developed as a true halo engine.
Internal Specifications
Variant-specific values are labeled. Engine families that span multiple years or RPOs can have different heads, cams, induction and rotating parts, so the exact code/year always takes priority.
Identification & Output
- Engine codes / RPO
- S24A (1956 Adventurer 341 dual four-barrel), S25 (1957 Firedome 341 2-barrel), S26 (1957 Fireflite 341 4-barrel)
- Casting numbers
- 1635779 (341 cylinder-head reference), 1730414 (1957 341 intake-manifold reference), 1636609 / 1735785 (341 crankshaft references); block is in the same tall-deck family as the 330 and is best verified with its S-series stamp
- Power rating
- SAE gross (period factory rating)
- Horsepower RPM
- 320 hp @ 5200 rpm in 1956 Adventurer; 270 hp @ 4600 rpm 1957 Firedome; 295 hp @ 4600 rpm 1957 Fireflite/Power Pack
- Torque RPM
- 356–365 lb-ft @ 4000 rpm in period 1956 Adventurer references; 350 lb-ft @ 2400 rpm 1957 Firedome; 390 lb-ft @ 2400 rpm 1957 Fireflite/Power Pack
Operating Specs
- Production notes
- The 341 began as the dual-quad 1956 Adventurer engine, created by enlarging the 330 bore while retaining the 3.80-inch stroke. In 1957 the 341 moved into Firedome and Fireflite production while the Adventurer grew again to 345 cid.
Compatibility Notes
- The 341 uses the tall-deck 330/341/345 DeSoto Hemi architecture; it does not share intake-manifold dimensions with the 276/291 short-deck group.
- Adventurer hardware—including dual-quads, camshaft, valve springs, pistons and strengthened rotating components—differs from ordinary Firedome/Fireflite 341 combinations.
Notable Applications
1956 DeSoto Adventurer1957 DeSoto Firedome1957 DeSoto FireFlite
Strengths
- 320-hp Adventurer configuration
- Large-valve performance potential
- Strong period high-speed capability
Weaknesses / Watch-outs
- Dual-quad hardware is rare
- Heavy and wide
- Specialist early-Hemi parts ecosystem
Common Upgrades
- Dual-quad restoration
- Modern ignition
- Internal oiling and valvetrain updates
Racing History & Legacy
A prototype equipped with the 341 Adventurer powertrain reportedly reached 137 mph at Daytona and 144 mph at Chrysler's Chelsea proving grounds; this is best treated as period performance testing rather than a production-car certification.
The 341 transformed DeSoto’s Hemi from a strong luxury-car engine into a genuine high-performance flagship and established the Adventurer as the division’s answer to Chrysler’s 300 series.
References & Image Credit
Engine image: Joe Ross · CC BY-SA 2.0 · source
Hemmings — 1956 DeSoto Adventurer
historical reference
Hot Rod — Hemi engine sizes
technical history
Over-Drive Magazine — AMA/brochure-backed 1956–1957 DeSoto 341 specifications
period spec compilation
Quality Engineered Components — DeSoto early Hemi engine ID codes
specialist identification reference
Quality Engineered Components — DeSoto Hemi cylinder-head casting numbers
specialist technical reference
Quality Engineered Components — DeSoto Hemi intake casting numbers
specialist technical reference
Quality Engineered Components — DeSoto Hemi crankshaft references
specialist technical reference
Hot Heads — DeSoto short-deck and tall-deck intake compatibility
aftermarket technical reference
National DeSoto Club — 1956 Adventurer and DeSoto engine history
club history
Mac's Motor City Garage — 1956 Adventurer Daytona/Chelsea performance testing
historical performance reference
Over-Drive Magazine — 1957 DeSoto AMA/brochure-backed specifications
period spec compilation
Key Factory / Build Variants
S25 341 Firedome
1957270 hp @ 4600 rpm
Two-barrel production version
S26 341 Fireflite
1957295 hp @ 4600 rpm
Four-barrel higher-output production version
Engineering Notes Worth Knowing
01
341 cu in / 5.6 L with 3.78 x 3.80-inch bore and stroke.
02
Tall-deck OHV Hemi V8 with dual rocker shafts.
03
Adventurer versions used dual four-barrel carburetors and 9.25:1 compression.
04
1956 Adventurer rating: 320 hp and 356 lb-ft.
History · context · related reading
The Story Behind DeSoto 341 Hemi
The 341 Adventurer changed DeSoto's image. Dual quads and more than 300 horsepower turned the division's Hemi from a strong luxury engine into a legitimate high-performance flagship.
TorqueList Garage Reference Series
See this engine inside the full DeSoto reference catalog.
The same Engine Library data now powers a more detailed mobile-friendly catalog with technical specs, variants, engineering notes, history and related stories.