Build catalogue
George Smathers' 1971 TR6 Ford 302 V8 Conversion
britishv8.orgas published in BritishV8 Magazine, Volume XIX Issue I, December 2011
Photo: britishv8.orgA 1971 Triumph TR6 rebuilt around a Ford 302 V8
George Smathers spent seventeen months fitting a Ford 302 crate V8 and a Tremec five-speed into his TR6, mounting the engine further back than usual to avoid a hood scoop and keep the oil drain plug above the frame rails. The write-up details the custom transmission tunnel he fabricated, the Goodparts-based rear end and suspension, and the Wilwood brake upgrades, alongside interior and electrical work. It is a useful reference for anyone considering a similar low-profile small-block V8 swap into a TR6.
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 5
- Ford 302 crate engineFord
Factory crate engine rated 350hp, base of the V8 conversion
- Edelbrock RPM aluminum cylinder headsEdelbrock
60cc combustion chambers with bronze guides fitted to the 302
- Cobra Powered By Ford aluminum valve coversCobra
Fitted to the small block Ford
- Dan Masters style motor mounts
Used to mount the engine rearward in the chassis
- Serpentine fan belt
Drives accessories on the V8
Fuel & Ignition 6
- Edelbrock Performer intake manifoldEdelbrock
Fitted atop the 302
- Edelbrock 600cfm carburetor (model 1406)Edelbrock
Carburetor with electric choke feeding the engine
- Edelbrock electric fuel pumpEdelbrock
Supplies fuel to the carburetor
- Pertronix Flame-Thrower II Billet Distributor (model D130710)Pertronix
Ignition distributor for the V8
- Accel Super Stock ignition coilAccel
Ignition coil paired with the distributor
- Ford Racing spark plug wiresFord Racing
Ignition wiring for the engine
Cooling 1
- Griffin aluminum radiatorGriffin
Fitted with a 14-inch Pro Air pulling electric fan for cooling
Gearbox & Drivetrain 6
- Tremec T5 5-speed gearboxTremec
Manual transmission installed behind the V8
- Centerforce clutchCenterforce
Clutch used with the T5 gearbox
- Wilwood clutch master cylinderWilwood
Operates the hydraulic clutch system
- Tilton hydraulic throw-out bearingTilton
Part of the hydraulic clutch actuation
- Goodparts modified Nissan R200 differentialGoodparts
Viscous limited slip rear differential installed
- Goodparts axles and rear hubsGoodparts
Rear axle components fitted with the R200 diff
Suspension & Steering 6
- KYB shock absorbers (front)KYB
Front shocks fitted with lowered springs
- Goodparts lowered front springsGoodparts
Stiffer springs used in the front suspension
- Woodward steering shaftWoodward
Fitted with three u-joints and two Heim joints for support
- Goodparts lowered rear springsGoodparts
Stiffer springs used in the rear suspension
- KYB Gas-a-Just shock absorbers (rear)KYB
Rear shocks paired with lowered springs
- Blind Moose rear shock kitBlind Moose
Modified with extra support arms for the rear suspension
Brakes 5
- MP Master Brakes master cylinder and boosterMP Master Brakes
Braking system upgrade paired with a Wilwood proportioning valve
- Wilwood proportioning valveWilwood
Used with the MP Master Brakes master cylinder and booster
- Edelmann #272330 adapterEdelmann
Adapts American-thread brake lines to British threads
- Wilwood front brake calipersWilwood
Front brake upgrade
- Wilwood 10.75 x 0.81 inch solid rotorsWilwood
Front brake rotors fitted with the Wilwood calipers
Wheels & Tyres 2
- Konig Rewind 16-inch aluminum wheelsKonig
Wheels fitted to the car
- Falken ZIEX ZE912 tiresFalken
205/65/16 V-rated tires fitted to the Konig wheels
Body & Trim 1
- Four point roll bar
Fitted with a 3rd brake light for safety
Interior 7
- MotaLita steering wheelMotaLita
Steering wheel fitted in the cabin
- Mr. Roadster gas pedalMr. Roadster
Fitted with a Lokar cable for throttle control
- Lokar cableLokar
Throttle cable used with the Mr. Roadster gas pedal
- Hurst gear selectorHurst
Shifter fitted to the Tremec T5
- Miata seats
Seats with integrated heaters and speakers installed in the cabin
- Lizard Skin sound spray, heat spray and acoustic matLizard Skin
Applied for sound and heat insulation in the cabin
- Maradyne 5000 heaterMaradyne
Small heater mounted above the passenger footbox after the original heater no longer fit
Electrical 5
- Autometer Old Tyme electronic gaugesAutometer
Full gauge set including speedometer, tachometer, coolant temp, oil pressure, clock, fuel level and voltage
- Advance AutoWire wiring harnessAdvance AutoWire
Complete wiring harness for the car
- Delco-style single wire alternatorDelco
Charging system component
- Mustang inertia switchFord Mustang (part source)
Safety cutoff switch used in the electrical system
- TPI Tech 7-inch halogen (H4) headlightsTPI Tech
Headlights with built-in LED turn signal and parking lamps, replacing shaved stock signals
Other 2
- Speedway Motors Tight-Fit 4-into-1 headersSpeedway Motors
AHC coated inside and out, part of the 2-inch exhaust system
- Dynomax Turbo mufflersDynomax
Dual 18-inch mufflers used in the exhaust system
Photos
All 31 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
Setting the goals
George set two rules for the swap: keep the oil drain plug level with or above the bottom of the frame rails, and avoid cutting a bulge or scoop into the hood for carburetor clearance. To meet both, he installed the small block Ford further rearward in the chassis than most builders do.
Benefits of the rearward placement
Mounting the engine further back meant George did not need to cut the TR6's front crossmember, the stock engine brace stayed in place with only slight modification, cooling packaging was easier, and weight distribution improved. The tradeoff was less room for the pedals and a tighter cabin.
Engine and drivetrain build
The base was a factory Ford 302 crate engine rated at 350hp, fitted with Edelbrock RPM heads, an Edelbrock Performer intake and carburetor, and a Pertronix billet distributor. Power runs through a Tremec T5 five-speed with a Centerforce clutch and Tilton hydraulic throw-out bearing to a Goodparts-modified Nissan R200 limited-slip rear end.
Suspension, steering and brakes
The body was lifted 5/8 inch on hard rubber spacers to clear the engine while keeping the stock hood line. Goodparts supplied stiffer lowered springs front and rear, paired with KYB shocks and a modified Blind Moose rear shock kit. Steering uses a Woodward shaft with three u-joints and two Heim joints, and braking was upgraded with Wilwood calipers, rotors and a proportioning valve.
Fabricating the transmission tunnel
Because the engine sat deeper in the chassis, George designed and built his own transmission tunnel from 18 gauge mild steel sheet, using a framework of narrow steel strips to define the seams and bends. The fabrication also replaced the stock pressed-board firewall section, and after a trial fitting it was prepared for paint and leather.
Cooling, electrical and heating fixes
A Griffin aluminum radiator with a 14-inch pulling electric fan handles cooling, helped by a Lexan cover directing airflow from the cowl to the radiator; the engine runs at an indicated 180-185 degrees F. The new gearbox conflicted with the original heater location, so George fitted a small Maradyne 5000 heater above the passenger footbox, and wired the car with an Advance AutoWire harness and a Delco-style single wire alternator.
Interior and finishing touches
Inside, George fitted Miata seats with built-in heaters and speakers, a MotaLita steering wheel, a Hurst shifter, and a full set of Autometer Old Tyme gauges. Lizard Skin sound and heat spray plus acoustic mat were applied for comfort. He did all the mechanical and fabrication work himself but hired out sandblasting, bodywork and paint to Anderson's Collision of Spokane, Washington.
A summary in our own words. The full account, with all its detail, is the owner's: read it at britishv8.org ↗
Worth knowing
- Mounting the V8 further rearward avoids cutting the front crossmember and hood while improving weight distribution.
- Placing the engine deeper into the chassis can crowd the pedal box and cabin space.
- A custom-fabricated transmission tunnel can also solve firewall material and fitment issues at the same time.
- Relocating the engine may force relocation of accessories like the heater to a new spot such as above the footbox.
- Using a lightweight mock-up engine block makes trial fitting and measuring much easier before final installation.