Cadillac 331 V8 Pro Series Ready to Run Distributor

The TSP Pro Series Ready-to-Run Distributor for the Cadillac 331 V8 is a precision ignition upgrade for carbureted 331 CID (5.4L) Cadillac applications from the 1949 through 1955 model years. Built on a machined aluminum housing with a circuit board module and magnetic pickup trigger, this distributor provides accurate, repeatable ignition timing without the need for points, condenser, or a separate ignition control box.

Before ordering — 12-volt electrical system required. The Cadillac 331 was produced during an era when many vehicles left the factory equipped with 6-volt electrical systems. This distributor requires a 12-volt electrical system with a charging alternator and is not compatible with 6-volt systems, generators, or ballast resistors. If your Cadillac 331 vehicle has not been converted to a 12-volt alternator system, this distributor cannot be installed until that conversion is completed.

Counter-clockwise distributor rotation. The Cadillac 331 V8 runs counter-clockwise distributor rotation — the opposite of many domestic V8 engines. This affects rotor phasing and spark plug wire routing and must be accounted for during installation. Do not assume standard clockwise plug wire layout applies. Verify your firing order and wire routing for counter-clockwise operation before finalizing installation. Note that later Cadillac V8 engines — the 472 and 500 CID introduced in 1968 — run clockwise rotation. If you are working with a post-1967 Cadillac, a different TSP distributor is required.

The Pro Series design uses an external ignition coil, giving you flexibility to run a coil matched to your build level. A minimum coil output of 35,000 volts is required — coil is not included. Three advance bushings and four advance springs are included, allowing the mechanical advance curve to be tuned for your specific engine combination. A vacuum advance block-off plate and tachometer output extension cable are also included.

 

The Cadillac 331 V8 — Production Era and What Buyers Need to Know Before Ordering
The Cadillac 331 CID (5.4L) V8 was introduced in 1949 as Cadillac's first modern overhead valve V8 and remained in production through 1955, powering the Series 62, Series 75, Fleetwood, Fleetwood 60 Special, Coupe de Ville, and the limited-production Eldorado. It is a foundational engine in American automotive history and remains an active restoration and custom build platform. Two things define this distributor purchase above all others for the 331 era: the 12-volt electrical system requirement and the counter-clockwise rotation.

12-Volt Conversion — Verify Before Ordering
Many 1949–1955 Cadillac vehicles left the factory equipped with a 6-volt electrical system. This Pro Series distributor requires a 12-volt system with a charging alternator. It is not compatible with 6-volt systems, generators, or ballast resistors. If your vehicle has not been converted to 12-volt, that conversion must be completed before this distributor can be installed. Verify your vehicle's electrical system before ordering.

Counter-Clockwise Rotation — Installation Critical
The Cadillac 331 runs counter-clockwise distributor rotation. When installing this distributor, verify your rotor direction and spark plug wire routing for counter-clockwise operation. Do not use clockwise wire routing assumptions — incorrect plug lead installation based on clockwise rotation will cause misfires across multiple cylinders.

Performance Benefit
The circuit board module and magnetic pickup trigger deliver precise, repeatable spark timing without the wear and drift that accumulates in aging points-based systems — a meaningful improvement on 70-plus-year-old ignition hardware. Three advance bushings and four advance springs allow full adjustment of the mechanical advance curve, which is particularly valuable on modified 331 builds running aftermarket camshafts or performance carburetors. A vacuum advance block-off plate is included for performance applications. A tachometer output extension cable simplifies aftermarket tach wiring.

COMPATIBLE WITH
CADILLAC V8
• 5.4 L / 331 in3

NOTES
• Fits all 1949–1955 Cadillac 331 V8 applications.
• Not compatible with later Cadillac 365, 390, or 429 V8 engines.
• Designed for carbureted ignition systems only.
• Requires a 6-volt electrical system for 1949–1952 applications; 12-volt for 1953–1955 applications.
• It is not compatible with a generator and cannot be used with a ballast resistor.
• Verify distributor gear compatibility with camshaft material before installation.

COMMON VEHICLE APPLICATIONS
Cadillac Series 61 (1949–1951)
Cadillac Series 62 / Coupe DeVille (1949–1955)
Cadillac Series 60 Special / Fleetwood (1949–1955)
Cadillac Series 75 / Commercial Chassis (1949–1955)
Cadillac Eldorado (1953–1955)

SPECIFICATIONS
Trigger Type: Circuit Board Module with Magnetic Pick-Up
Distributor Rotation: Counter-Clockwise
Advance Type: Mechanical and Vacuum
Cap Color: Available in Black, Blue, Red
Terminal Gender: Male
Mechanical Tach Drive: No
Slip Collar: No
Coil Included: No
Coil Type: External
Required Coil Output: 35,000+ V
Gear Material: Steel
Housing Material: Machined Aluminum
Ignition Box Required: No
Marine Use: No
Cylinders: 8
3 Bushings And 4 Springs for Mechanical Advance: Included
Color-Matched Spark Plug Wire Retainer with Screws: Included
Vacuum Advance Block-Off Plate (Black): Included
Power Extension Cable: Included
Tachometer Output Extension Cable: Included