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Larry Breitkreitz's 1973 Spitfire, with Toyota 4AGE 4-cylinder

Larry Breitkreitz · 1973 Triumph Spitfire 1500

Triumph Spitfire

britishv8.orgas recorded by Dan Masters

Read the full write-up at britishv8.org ↗

Photo: britishv8.org

A 1973 Triumph Spitfire rebuilt with a Toyota 4AGE twin-cam engine

Larry Breitkreitz rescued a Spitfire that a previous owner had butchered trying to fit a Mazda rotary, and instead built a clean, factory-looking car around a Toyota 4AGE twin-cam four and its five-speed gearbox. The write-up is worth reading for the detailed frame, cooling, wiring and exhaust fabrication needed to make a Japanese drivetrain disappear into a British body, blending Lucas and Nippondenso electrics into a single working system.

Specs

As the owner states it.

Engine
Toyota 4AGE DOHC 16-valve 1600cc, fuel injected, about 124 hp
Gearbox
Toyota 5-speed manual
Cooling
Mazda RX-7 radiator with custom left-offset mount, Pontiac 6000 fan, Toyota oil cooler
Suspension
Corvette air shocks, Ford Fox-series rear sway bar with custom mounts
Wheels
Powder coated, stock-sized tyres
Body
Frame stripped, sandblasted and repainted; body repaired
Paint
Acrylic enamel, Honda Milano Red
Interior
Reupholstered seats from Moss or Victoria British parts, custom carpet, insulated floor and transmission tunnel
Electrical
Combined Lucas and Nippondenso ("Nippo-Lucas") wiring, Toyota engine computer mounted under dash

Parts used

What the owner names in the write-up, grouped the way the Parts page groups them. Where one of the shops we index lists the same thing for this car, it is shown underneath with a link to the shop.

Engine 1

  • Toyota 4AGE DOHC 16-valve engineToyota

    Replaced the original Spitfire engine, close to stock displacement but nearly double the power

Fuel & Ignition 1

Cooling 3

Gearbox & Drivetrain 1

Suspension & Steering 2

  • Corvette air shocksCorvette

    Fitted in place of stock shocks, inflated as required

  • Ford Fox-series rear sway barFord

    Fitted with custom mounts to stiffen the rear end

    In the shops
    Sway Bar U-Bolt ↗Moss Motors – Triumph TR6/TR250· $4.15 USD
    Sway Bar, 7/8 inch diameter ↗Moss Motors – Triumph TR6/TR250· $171.75 USD
    Sway Bar to Wishbone Link, Left ↗Moss Motors – Triumph TR6/TR250· $14.25 USD

Interior 1

Electrical 1

  • Toyota engine management computerToyota/Nippondenso

    Mounted under the left side of the dashboard, running the Nippondenso engine control system

Other 1

  • Custom exhaust header and system

    Fabricated from the engine manifold outlets, with muffler and resonator for a quiet exhaust

Photos

All 8 pictures in the write-up, in the order they were posted, shown from britishv8.org. A picture opens larger here, with the way through to the page it is on.

Larry Breitkreitz's 1973 Spitfire, with Toyota 4-cylinderPhoto: britishv8.org
Toyota DOHC, 16 valve 4AGE enginePhoto: britishv8.org
MR2 DOHC 4AGE 1600cc enginePhoto: britishv8.org
Dash instruments are stock SpitfirePhoto: britishv8.org
Mazda RX-7 radiatorPhoto: britishv8.org
Toyota Twin-Cam 16 valve enginePhoto: britishv8.org
1973 Triumph SpitfirePhoto: britishv8.org
Donate Now!Photo: britishv8.org

How it was done

Starting point

Larry took on a Spitfire that had been badly damaged by a previous owner attempting a Mazda RX-7 rotary conversion, with the engine left sitting in a hole hacked into the firewall and floor. The drivetrain he used instead, a Toyota 4AGE twin-cam engine and five-speed gearbox, came from someone restoring a crashed Corolla GTS who only needed the body.

Why the 4AGE

The Toyota 4AGE is a DOHC 16-valve engine also used in the MR2, displacing close to the Spitfire's original 1600cc but producing about 124 hp, nearly double stock output. It is fuel injected and computer controlled, making it quiet, smooth and economical, and it is lighter than the Triumph engine it replaced.

Fitting the engine

The body was lifted off the frame, which was stripped, sandblasted and painted. The new engine was hung from a chain above the bare frame to work out its position by trial and error, with the body test-fitted repeatedly and the hood checked for clearance. The work was aimed at keeping the finished car looking completely stock.

Frame modifications

The crossmember under the engine was replaced with two fabricated tubular units either side of the sump. Steering rack mounts were lowered half an inch, the frame was plated for a rerouted speedo cable, and notched for the clutch slave cylinder. Fabricated steel engine mounts, a modified Toyota mount, and a narrowed Toyota transmission mount were welded in, along with Corvette air shocks and a Ford Fox rear sway bar.

Cooling and induction

A Mazda RX-7 radiator was mounted off to the left on a custom support and shield, cooled by a Pontiac 6000 fan controlled by the Mazda sensor. The Toyota oil cooler sat ahead of the radiator on custom hoses. The air cleaner and mass air sensor were mounted forward on the left, feeding the intake plenum through stock Toyota tubes, with custom steel shields replacing the original cardboard engine covers.

Exhaust and interior fabrication

Larry built a custom header from the engine manifold to a quiet custom exhaust system with muffler and resonator. Inside, the cardboard transmission tunnel was replaced with a steel one, and the interior and floor were insulated against noise and heat.

Wiring

Combining stock Lucas wiring with the Toyota's Nippondenso engine control system was one of the biggest jobs. The Toyota computer was mounted under the left side of the dashboard, with Nippondenso relays and harnesses retained where needed. The Lucas dash wiring and instruments, including the tachometer, remained stock and interface with the Japanese system, notably at the ignition switch.

Interior and finish

Seats and interior trim were refreshed with parts from Moss or Victoria British, then locally reupholstered to the original pattern, while the carpet was made from scratch to fit the new transmission tunnel shape. The body was repaired and painted in Honda Milano Red acrylic enamel, bumpers were rechromed, wheels powder coated, and badges and decals left off for a cleaner look.

A summary in our own words. The full account, with all its detail, is the owner's: read it at britishv8.org ↗

Worth knowing

  • Test-fit the engine and body repeatedly with the engine hung on a chain to get placement right.
  • Keep as much of the original wiring as possible and interface it carefully with the donor engine's own electronics.
  • Fabricate steel shields and tunnels rather than reuse cardboard originals for a tidier, more durable result.
  • Sourcing an engine and gearbox from someone parting out a crashed donor car can be a practical and affordable route.
  • A lighter, more powerful engine can improve handling balance as well as performance.

britishv8.org

Read in full on 5 September 2026. The work, the words and the pictures are Larry Breitkreitz’s; this page is a catalogue of them in our own words, and a signpost.

Read the full write-up at britishv8.org ↗

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