Build catalogue
Barry's Triumph Spitfire V6 Conversion
britishv8.orgas recorded by Dan Masters, reprinted from a Triumphs/Spitfires mailing list post
Photo: britishv8.orgA Triumph Spitfire converted to a Ford 2.8 EuroV6
Barry converted his Triumph Spitfire to run a Ford Cologne 2.8 V6 from a Mustang, working through engine mounting, bellhousing and transmission tailshaft changes, and a run of rear-end failures that led him to redesign the rear suspension around GT6+ independent geometry with TR6 axles. The write-up is useful for its detail on oil pan clearance, bellhousing surgery for a hydraulic clutch, and the eventual move to a Quaife diff and T5 gearbox.
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 6
- Ford 2.8 Cologne V6 engineFord
Almost stock, used as the swap engine with mild street cam and tube headers
- Mild street camshaft
Fitted to the 2.8 V6 for a mild performance upgrade
- Tube headers
Required for the engine to fit in the Spitfire frame
- Capri rear-sump oil pan and oil pump assemblyFord Capri
Required version of pan/pump for the installation, further notched for frame and steering rack clearance
In the shops
Oil Pump Assembly, Standard Specification ↗
Racetorations· £66.00 GBP
Racetorations Toleranced Aluminium Oil Pump Assembly (TR5-6) ↗
Racetorations· £220.00 GBP
Oil Pan/Sump Gasket Set (948 and early 1098) ↗
bpnorthwest.com· $5.55 USD - GT6/TR6 engine mountsTriumph
Used at stock frame mounting locations with new brackets to hang the V6
In the shops
Fan Eliminator Kit with Grade 8 Bolt (TR6/TR250/GT6) ↗
pattonmachine.com· $45.00 USD
Fan Eliminator Kit with Grade 5 Bolt (TR6/TR250/GT6) ↗
pattonmachine.com· $40.00 USD
Timing Cover Gasket (TR5-TR6) ↗
Racetorations· £2.00 GBP - TRW heavy-duty high-capacity oil pumpTRW
Handles oiling along with synthetic oil
In the shops
High Capacity Water Pump with Bypass ↗
bpnorthwest.com· $61.76 USD
Tri-Metal Heavy Duty Main Bearings (STD) ↗
bpnorthwest.com· $108.61 USD
Cylinder Head Nut, Flanged, Heavy Duty (ARP) ↗
Moss Motors – Triumph TR6/TR250· $3.55 USD
Fuel & Ignition 2
- Weber 40 DFAV carburetorWeber
Siamesed throttle openings feed the modified single-plenum intake manifold
In the shops
Weber Downdraft Carburetor Conversion Kit, 1500 ↗
Moss Motors – Triumph TR6/TR250· $631.25 USD
Weber 45 DCOE Side-Draft Carburetor Conversion Kit ↗
Moss Motors – Triumph TR6/TR250· $1,366.75 USD
Weber Downdraft Carburetor Conversion Kit, Water Choke ↗
Moss Motors – Triumph TR6/TR250· $631.25 USD - Modified stock intake manifold
Milled half an inch on the carb flange and internal divider removed to combine plenums for hood clearance
In the shops
Intake & Exhaust Manifold Gasket, TR6 72-76 / GT6 ↗
bpnorthwest.com· $23.99 USD
Intake & Exhaust Manifold Gasket (TR6 1972-1976, GT6) ↗
bpnorthwest.com· $4.55 USD
Intake/Exhaust Manifold Gasket ↗
bpnorthwest.com· $8.99 USD
Cooling 2
- Custom four-tube crossflow radiator
Large custom radiator built to cool the V6 swap
In the shops
Koyo Crossflow Radiator Drain Plug ↗
Flyin' Miata· $12.99 USD
Koyo Crossflow Radiator Drain Plug ↗
Flyin' Miata· $12.99 USD
NB Fan Mounts for Crossflow Radiator (Pair) ↗
Flyin' Miata· $12.99 USD - Dual thermostatically controlled electric fans
Paired with the custom radiator to prevent overheating
Gearbox & Drivetrain 11
- Borg-Warner SR-4 Mustang V6 four-speed transmissionBorg-Warner
Used with stock Mustang V6 gear ratios
In the shops
Borg & Beck Clutch Kit ↗
Moss Motors – Triumph TR6/TR250· $210.00 USD
Borg & Beck Clutch Kit ↗
Moss Motors – Triumph TR6/TR250· $212.00 USD
Rear Transmission Seal, Spitfire/GT6/TR7 4-speed/Midget 1500 ↗
bpnorthwest.com· $2.36 USD - Courier/Ford/Mazda clutch slave cylinderFord/Mazda
Mounted on a fabricated bracket to keep hydraulic clutch actuation
In the shopsClutch Slave Cylinder Mounting Kit (GT6) ↗
bpnorthwest.com· $4.72 USD
Clutch Slave Cylinder (TR3 Late, TR4, TR4A, GT6) ↗
bpnorthwest.com· $21.95 USD
Long Throw Clutch Slave Cylinder (TR3 Late-TR4A, GT6) ↗
bpnorthwest.com· $31.99 USD - 1978 AMC Spirit tailshaft extension and mainshaftAMC
Swapped in to relocate the shift lever to the stock Triumph position
- Custom transmission yoke
Made to match Triumph's smaller u-joints after the tailshaft swap
In the shopsJoint Yoke, Manual Transmission ↗Motaclan Limited· £0.00 GBP
Joint Yoke (Manual Transmission) ↗Motaclan Limited· £0.00 GBP
- Custom transmission cross member
Manufactured around the 1978 transmission mount
In the shops
Floor Cross Member ↗
Moss Motors – Triumph TR6/TR250· $116.25 USD
Cross Member Stud Plate ↗
bpnorthwest.com· $1.69 USD
Chequer Plate Rear Cross Member, 2mm ↗
Moss Motors – Triumph TR6/TR250· $62.50 USD - Shortened propshaft/driveshaft
Cut to the length required for the new transmission position
In the shops
Propshaft/Driveshaft Nut & Bolt ↗
TRGB· £2.31 GBP - Capri 2600 starter motorFord Capri
Smaller starter welded into a modified bellhousing section for frame clearance
- TR6 sliding axle shafts and u-jointsTriumph TR6
Replaced rotoflex couplings and axles by re-manufacturing hubs and diff flanges for stronger joints
In the shops
Timing Cover Gasket (TR5-TR6) ↗
Racetorations· £2.00 GBP
Oil Gallery Plug, LH Side (TR5-TR6) ↗
Racetorations· £2.50 GBP
Front Stub-Axle D-Washer (Triumph range) ↗
Racetorations· £2.25 GBP - Quaife torque-sensing differentialQuaife
Installed as a later upgrade, requiring a change to 3:63 diff gears
In the shops
Quaife 'Dog' Gear Set (Dolomite Sprint) ↗
Racetorations· £3,092.93 GBP
Racetorations Quaife Competition 'Dog' Gearbox (Dolomite Sprint) ↗
Racetorations· £4,500.00 GBP - 3:63 differential gears
Replaced original 3:27 gears because the Quaife diff would not accept them
In the shops
Differential Planet Gear ↗
Moss Motors – Triumph TR6/TR250· $23.99 USD
Differential Planet Gear ↗
Moss Motors – Triumph TR6/TR250· $0.00 USD
Differential Pin and Spider Gear Set - Mini 1980 on ↗
bpnorthwest.com· $97.09 USD - Borg-Warner T5 five-speed transmissionBorg-Warner
Later installed in place of the SR-4, needing frame trimming and tunnel fabrication
In the shops
Borg & Beck Clutch Kit ↗
Moss Motors – Triumph TR6/TR250· $210.00 USD
Borg & Beck Clutch Kit ↗
Moss Motors – Triumph TR6/TR250· $212.00 USD
Rear Transmission Seal, Spitfire/GT6/TR7 4-speed/Midget 1500 ↗
bpnorthwest.com· $2.36 USD
Suspension & Steering 2
- GT6+ independent rear suspensionTriumph
Adapted in place of the swing-spring rear end, with new wishbone and shock mounting brackets
In the shops
Single Port Thermostat Riser (Triumph GT6) ↗
pattonmachine.com· $80.00 USD
Fan Eliminator Kit with Grade 8 Bolt (TR6/TR250/GT6) ↗
pattonmachine.com· $45.00 USD
Fan Eliminator Kit with Grade 5 Bolt (TR6/TR250/GT6) ↗
pattonmachine.com· $40.00 USD - Quarter inch wheel spacers
Fitted at the rear upper shock locations to clear wider tyres, setting a 49.5 inch rear track
Photos
All 7 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.
How it was done
Engine choice and fitment
Barry used an almost stock Ford 2.8 EuroV6 with a mild street cam and tube headers. The oil pan needed notching at the front for the steering rack and at an angle on the right for the suspension mount. He used the Capri rear-sump pan and oil pump, and GT6/TR6 engine mounts on stock frame mounting locations with new brackets.
Cooling and intake
Cooling is handled by a custom four-tube crossflow radiator with dual thermostatically controlled electric fans, which he says keeps the car from overheating even in hot weather. The intake manifold was milled about half an inch for clearance and its internal divider removed to join the two plenums into one, feeding a Weber 40 DFAV carburettor on regular unleaded fuel.
Bellhousing and clutch
To keep a hydraulic clutch instead of the Mustang's cable setup, Barry machined the bellhousing starter area, welded in a new mount for a smaller Capri starter, and redrilled and tapped it. He also moved the throwout bearing arm to the other side of the bellhousing and fitted a Courier/Ford/Mazda clutch slave cylinder on a fabricated bracket.
Transmission and driveshaft
He kept the stock Mustang V6 gear ratios in a Borg-Warner SR-4 four speed, changing the tailshaft extension to a 1978 AMC Spirit unit so the shift lever landed in the stock Triumph location, which also needed a new mainshaft and a custom transmission yoke for Triumph's smaller u-joints. A new cross member was made around the 78 transmission mount, and the driveshaft was shortened to suit.
Rear suspension and axle troubles
The rear end proved the weak link, with Barry destroying three carriers before getting it right. Running the stock swing-spring rear suspension was workable with a 76-or-later carrier, but he instead adapted the fully independent GT6+ rear suspension, fabricating new lower wishbone and upper shock mounting brackets and adding quarter inch spacers to set a 49.5 inch rear track.
Driveline durability upgrades
Tired of replacing rotoflex couplings roughly every three months under the V6's torque, Barry re-manufactured the hubs and differential flanges to run TR6 sliding axle shafts with their stronger u-joints instead. He later fitted a Quaife torque-sensing differential, which required swapping the 3:27 diff gears for 3:63 since the Quaife would not accept the original ratio.
Ongoing evolution
With the lower 3:63 gearing, Barry felt he really needed the overdrive of a five-speed, and a footnote confirms he later installed a Borg-Warner T5, involving frame trimming, tunnel fabrication and further machining, which he considered well worth the effort for this engine and rear-end ratio.
A summary in our own words. The full account, with all its detail, is the owner's: read it at britishv8.org ↗
Worth knowing
- Use the Capri rear-sump oil pan and pump, not the standard Mustang pan, for frame clearance.
- Expect the swing-spring rear end to be the weak point; a later carrier (76-on) is needed if kept stock.
- Rotoflex couplings will not survive the V6's torque for long; stronger TR6 sliding axle shafts and u-joints are worth the rework.
- A Quaife diff will not accept the stock 3:27 gears, so budget for a ratio change to 3:63.
- Moving to a five-speed like the T5 pays off with the lower diff ratio, but it is a much bigger job than the original four-speed swap.