S23 Firedome 330
1956230 hp / 305 lb-ft
Two-barrel tall-deck production version
DeSoto 330 Hemi enginePhoto: Greg Gjerdingen · CC BY 2.0
DeSoto · FireDome / FireFlite Hemi
DeSoto 330 Hemi
The 1956 long-stroke DeSoto Hemi that raised output to 230–255 horsepower before the Adventurer 341 arrived.
330
Cubic inches
The 330 introduced the 3.80-inch stroke used by DeSoto's final high-performance Hemi displacements and served as the direct base for the 341 Adventurer package.
Key variants
All variantsS23 Firedome 330S24 Fireflite 330
Displacement
330 ci
Bore
3.72"
Stroke
3.8"
Years
1956
Key Takeaway
The 330 introduced DeSoto's taller-deck Hemi layout with a 3.72-inch bore and longer 3.80-inch stroke. The revised architecture added substantial torque and provided the bottom-end dimensions used by the later 341 and 345 performance engines.
Technical Specifications
- Compression
- 8.5:1
- Horsepower
- 230 hp @ 4400 rpm Firedome; 255 hp @ 4400 rpm Fireflite
- Torque
- 305 lb-ft @ 2800 rpm Firedome; 350 lb-ft @ 3200 rpm Fireflite
- 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
- Two- and four-barrel carburetion
- Firing order
- 1-8-4-3-6-5-7-2
- Main bearings
- 5
The 330 introduced DeSoto's taller-deck Hemi layout with a 3.72-inch bore and longer 3.80-inch stroke. The revised architecture added substantial torque and provided the bottom-end dimensions used by the later 341 and 345 performance engines.
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
- S23 (1956 Firedome 330 2-barrel), S24 (1956 Fireflite 330 4-barrel)
- Casting numbers
- 1636629 (330 block reference), 1635779 (330 cylinder-head reference), 1636620 / 1686620 (330 4-barrel intake references), 1635785 / 1636609 (330 crankshaft references)
- Power rating
- SAE gross (period factory rating)
- Horsepower RPM
- 230 hp @ 4400 rpm Firedome; 255 hp @ 4400 rpm Fireflite
- Torque RPM
- 305 lb-ft @ 2800 rpm Firedome; 350 lb-ft @ 3200 rpm Fireflite
Operating Specs
- Production notes
- New for 1956, the 330 combined the existing 3.72-inch bore with a longer 3.80-inch stroke. Firedome and Fireflite versions used different carburetion and output levels, while the same basic tall-deck family was enlarged for the Adventurer.
Compatibility Notes
- The 330 belongs to the tall-deck DeSoto Hemi family with the 341/345; its intake-manifold family is separate from the shorter 276/291 engines.
- Although 330/341/345 share major architecture, compression, induction, camshaft, crank/rod details and external hardware vary by exact S-series application.
Notable Applications
1956 DeSoto Firedome1956 DeSoto FireFlite
Strengths
- Strong low-rpm torque
- Improved output over 291
- Direct lineage to Adventurer engine
Weaknesses / Watch-outs
- One-year displacement
- Heavy Hemi valvetrain
- Rare original components
Common Upgrades
- Four-barrel carburetion
- Improved exhaust
- Modern ignition
Racing History & Legacy
The standard 330 was a production luxury/performance engine rather than DeSoto’s dedicated 1956 speed package. Its taller-deck architecture, however, provided the foundation for the 341 Adventurer Hemi that DeSoto used for its highly publicized Daytona and proving-ground speed demonstrations.
The 330 introduced the taller-deck DeSoto Hemi architecture that supported the 341 and final 345-cid Adventurer engines.
References & Image Credit
Engine image: Greg Gjerdingen · CC BY 2.0 · source
Hot Rod — Hemi engine sizes
technical history
Hemmings — 1956 Adventurer development
historical reference
Over-Drive Magazine — AMA/brochure-backed 1956 DeSoto 330 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
Over-Drive Magazine — 1952–1961 DeSoto V8 engine facts
period spec compilation
Key Factory / Build Variants
S24 Fireflite 330
1956255 hp / 350 lb-ft
Four-barrel higher-output version
Engineering Notes Worth Knowing
01
330 cu in / 5.4 L with 3.72 x 3.80-inch bore and stroke.
02
Tall-deck 90-degree OHV DeSoto Hemi.
03
Two- and four-barrel carburetion.
04
Factory output ranged from 230 hp / 305 lb-ft to 255 hp / 350 lb-ft.
History · context · related reading
The Story Behind DeSoto 330 Hemi
The 330 was the engine that moved DeSoto's Hemi family into a more serious performance phase. Its longer stroke and taller deck created the foundation for the Adventurer engines that followed.
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.