Build catalogue
Mike Reynolds's 1974 Spitfire - Chevy V6 Conversion
britishv8.orgas published in BritishV8 Magazine, Volume XVII Issue 1, July 2009
Photo: britishv8.orgA 1974 Triumph Spitfire rebuilt on a custom chassis for a stroked Chevy V6
Mike Reynolds fitted a bored and stroked 4.8L Chevrolet V6 into a 1974 Spitfire, built on a complete custom drag-legal chassis rather than the stock frame. The result is a car that runs mid 11-second quarter miles and still handles and drives on the street, which is what makes the build notable given how much work went into both ends of that equation. He built and tuned the car himself, documenting the chassis, driveline and body work in detail.
Specs
As the owner states it.
- Engine
- 4.3L Chevrolet V6 bored and stroked to 4.8L, Bow Tie block, BRC billet crank, Comp Cams solid roller cam, Bow Tie aluminum heads, 11.2:1 compression, AED 650cfm carburetor
- Cooling
- Custom 19.5x20.5 inch 2-row aluminum radiator with Flex-A-Lite #150 fan
- Exhaust
- 1.75 inch headers into 2.5 inch pipes through a single Flowmaster 42582 muffler
- Transmission
- GM 200-4R automatic overdrive, TCI/TCS built, TCS 2800 stall converter, 3 inch aluminum driveshaft
- Rear End
- Narrowed Dodge 8.75 inch axle, 3.91:1 gears, Auburn Pro-Series limited slip differential
- Chassis
- Complete custom chassis built to NHRA and IHRA requirements, chromed and welded roll hoop
- Front Suspension
- Chris Alston (Ford Pinto) twin A-arm, 24 inch frame rail width, QA1 single adjustable shocks
- Rear Suspension
- Custom Bears Performance Products adjustable 4-link with wishbone locator, QA1 single adjustable shocks
- Brakes
- 1991 Ford Taurus master cylinder, adjustable proportioning valve; front Wilwood 1989 Camaro spec discs, 11 inch rotors; rear Wilwood Pro Street discs, 12 inch rotors
- Wheels/Tires
- Street: 16x8.5 ASA with 205/45 front, 245/45 rear Avon tires. Strip: 15x8 Bogart rims with Mickey Thompson 24x9 slicks rear
- Body
- All badges removed, wheel arches opened 2 inches, new dashboard and transmission tunnel
- Electrical
- VDO and Stewart Warner gauges, Panasonic head unit, Elemental Design speakers, Audisson amplifier, Optima Red Top battery, 80Amp Nippendenso alternator
- Weight
- 2312 lbs with driver, 48% front / 52% rear
- Performance
- Mid 11-second quarter miles without nitrous, 145mph achieved, 1.43 second 60-foot times on slicks
- Miles Driven
- About 2300 kilometers as of March 2009
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.
Shop suggestions are being prepared. The owner's parts list is available below.
Engine 6
- Chevrolet Bow Tie engine blockChevrolet
Base block for the 4.3L to 4.8L bore and stroke build
- BRC Performance billet crankshaftBRC Performance
Provides the stroke, with common-pin rod journals requiring odd-fire ignition and cam
- Comp Cams solid roller camshaftComp Cams
255/262 duration at 0.050 inch, 0.625 inch lift, selected for the odd-fire configuration
- Childs&Alberts 6 inch connecting rodsChilds&Alberts
Connects crankshaft to pistons
- Federal Mogul pistonsFederal Mogul
Used with the stroker crank and rods
- Chevrolet Bow Tie aluminum cylinder headsChevrolet
Raised 23 degree ports, 2.10 inch intake and 1.62 inch exhaust valves
Fuel & Ignition 6
- MSD odd-fire racing distributorMSD
Required to match the odd-fire firing order created by the billet crank
- Chevrolet Bow Tie box-style cross ram intake manifoldChevrolet
Two-piece manifold mated to the carburetor
- AED 650cfm carburetorAED
Holley 4150-based carburetor used on the final setup
- Edelbrock Performer intake manifoldEdelbrock
Used in an earlier setup, replaced by the Bow Tie cross ram
- Carter 750cfm carburetorCarter
Paired with the earlier Edelbrock intake, limited to low 12-second times
- Edelbrock Performer RPM nitrous injection systemEdelbrock
Set up for a 100hp shot but rarely used due to NHRA class ET limits
Cooling 2
- Custom 2-row aluminum radiatorGuyons of Calgary
19.5 inch by 20.5 inch, built on custom mounts
- Flex-A-Lite #150 cooling fanFlex-A-Lite
Rated 2800cfm at 2200rpm
Gearbox & Drivetrain 5
- GM 200-4R automatic transmissionGM / TCI / TCS
Purpose-built with TCI and TCS parts, manual valve body in low gears, rated to 600hp
- TCS 2800 stall torque converterTCS
Matched to the built transmission
- 3 inch aluminum driveshaft
Connects transmission to rear axle
- Dodge 8.75 inch rear axleDodge
Narrowed and fitted with 3.91 gears and limited slip diff
- Auburn Pro-Series limited slip differentialAuburn
Fitted inside the narrowed Dodge axle
Suspension & Steering 3
- Chris Alston twin A-arm front suspensionChris Alston
Ford Pinto based design, 24 inch frame rail width
- Bears Performance Products 4-link rear suspensionBears Performance Products
Custom adjustable setup with wishbone locator
- QA1 single adjustable shocksQA1
Used front and rear
Brakes 3
- Ford Taurus brake master cylinderRaybestos (part 390049)
1991 non-ABS unit used with an adjustable proportioning valve
- Wilwood front disc brakesWilwood
1989 Camaro spec calipers with a bearing conversion kit for Mustang II spindles, 11 inch rotors
- Wilwood Pro Street rear disc brakesWilwood
12 inch rotors fitted to the Dodge axle
Wheels & Tyres 3
- ASA 16x8.5 wheelsASA / Avon
Street wheels with 205/45 front and 245/45 rear Avon tires
- Bogart 15x8 rimsBogart
Strip wheels paired with Mickey Thompson slicks
- Mickey Thompson 24x9 slicksMickey Thompson
Rear drag tires for the strip
Electrical 6
- VDO and Stewart Warner gaugesVDO / Stewart Warner
Mixed gauge set for instrumentation
- Panasonic head unitPanasonic
Car audio source unit
- Elemental Design speakersElemental Design
Car audio speakers
- Audisson amplifierAudisson
Powers the audio system
- Optima Red Top batteryOptima
Main battery for the electrical system
- 80Amp Nippendenso alternatorNippendenso
Sourced from a Toyota 4-Runner
Other 2
- 1.75 inch headers
Feed into 2.5 inch exhaust pipes
- Flowmaster 42582 mufflerFlowmaster
Single muffler giving a deep exhaust note at idle
Photos
All 21 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
The engine build
The base is a 4.3L Chevrolet V6 bored and stroked to 4.8L using a Bow Tie block and a BRC Performance billet crankshaft. Because the billet crank has common-pin rod journals like a V8, an odd-fire MSD distributor and a Comp Cams solid roller camshaft were required. Aluminum Bow Tie heads, Federal Mogul pistons and Childs&Alberts rods bring static compression to 11.2:1, fed by an AED 650cfm carburetor on a Bow Tie cross ram intake.
An earlier setup and the nitrous question
Some photos show an earlier configuration with an Edelbrock Performer intake and a 750cfm Carter carburetor, which only managed low 12-second quarter miles. An Edelbrock Performer RPM nitrous system was installed for a 100hp shot but rarely used, since NHRA bracket rules cap the car at 11-second ETs and nitrous would have pushed it into disqualification territory.
Cooling and exhaust
A custom aluminum radiator, built by the now-closed Guyons of Calgary, was mounted on custom brackets and paired with a Flex-A-Lite electric fan. Exhaust runs through 1.75-inch headers into 2.5-inch pipes and a single Flowmaster muffler, which the owner says gives the car a deep small-block sound at idle.
Transmission and rear end
Power goes through a purpose-built GM 200-4R automatic overdrive transmission, assembled from TCI and TCS parts to handle over 600hp, running a TCS 2800 stall converter and a 3-inch aluminum driveshaft. A narrowed Dodge 8.75-inch rear axle carries 3.91:1 gears and an Auburn Pro-Series limited slip differential.
Custom chassis and suspension
Rather than keep the stock Spitfire frame, Reynolds built a complete custom chassis to NHRA and IHRA specifications, including a roll hoop bent to shape, chromed, and welded in. Front suspension is a Chris Alston Ford Pinto twin A-arm setup, rear is a custom Bears Performance Products 4-link with wishbone locator, both using QA1 single adjustable shocks.
Brakes, wheels and body
Braking uses a 1991 Ford Taurus master cylinder with an adjustable proportioning valve, Wilwood front discs adapted to Mustang II spindles, and Wilwood Pro Street rear discs. Street wheels are 16x8.5 ASA with Avon tires, while strip duty uses 15x8 Bogart rims with Mickey Thompson slicks. The body had all badges removed, wheel arches opened 2 inches, and a new dashboard and transmission tunnel fitted.
Result
Finished, the car weighs 2312lbs with the driver aboard, split 48/52 front to rear. It runs mid 11-second quarter miles without nitrous, has been driven to 145mph, and posts 1.43-second 60-foot times on slicks, lifting the front wheels off the line. Reynolds says it handles well for its size and still drives comfortably day to day.
A summary in our own words. The full account, with all its detail, is the owner's: read it at britishv8.org ↗
Worth knowing
- Matching a billet crank's common-pin journals requires an odd-fire distributor and camshaft, not standard even-fire parts.
- A nitrous system can be counterproductive if class rules cap allowable ET, since it may push the car into a faster, disqualifying bracket.
- Building a complete custom chassis, rather than modifying the stock frame, made it possible to meet NHRA and IHRA safety requirements.
- A single well-chosen muffler can give a V6 the deep exhaust note usually associated with a small-block V8.
- Balancing show-quality finish with a genuinely drivable, track-capable car took considerably more effort than expected.