Build catalogue
Jason Hemphill's 1977 Triumph TR7 with Small Block Ford V8 Engine
britishv8.orgBritishV8 Magazine, Volume XVI Issue 2, October 2008
Photo: britishv8.orgA 1977 Triumph TR7 drag car built around a stroked Ford 302 V8
Jason Hemphill converted his TR7 into a quarter-mile racer by fitting a stroked Ford small block, a strengthened chassis with a rollcage and ladder-bar rear suspension, and a Ford 9 inch axle. The finished car weighs 2500 lbs with driver and runs low 11 second quarter mile times, making it a compact example of a British sports car turned into a serious drag machine.
Specs
As the owner states it.
- Engine
- Ford 302 stroked to 349 cid, Parker Funnel Web intake, Holley 830cfm carburettor, Comp solid flat tappet cam (0.592/0.592 lift), MSD ignition
- Cooling
- Griffin aluminum radiator, Ford Mustang spec
- Transmission
- Ford C-4 automatic, 3500 stall converter
- Rear End
- Ford 9 inch, 3.89 gears, full spool
- Suspension
- Ladder bars and coil overs
- Chassis
- 6 point rollcage plus 2x3 square tube frame from engine compartment back
- Wheels/Tires
- Weld Prostars, front 15x3.5, rear 15x12
- Weight
- 2500 lbs with driver
- Completed
- 2004
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 2
- Ford 302 stroked to 349 cidFord
Base engine built up in displacement to 349 cubic inches for the swap
- Comp solid flat tappet camshaftComp Cams
Cam with 0.592/0.592 inch lift installed in the engine
Fuel & Ignition 3
- Parker Funnel Web intake manifoldParker
Intake manifold fitted to the stroked 302
In the shops
Intake Manifold Gasket ↗
Moss Motors – Triumph TR6/TR250· $19.99 USD
Intake Manifold O-Ring, TR7 ↗
bpnorthwest.com· $3.23 USD
Intake Manifold Gasket - TR7 ↗bpnorthwest.com· $3.39 USD - Holley 830cfm carburettorHolley
Carburettor feeding the V8
- MSD ignitionMSD
Ignition system fitted to the V8
Cooling 1
- Griffin aluminum radiatorGriffin
Mustang-spec radiator used to cool the swapped V8
In the shops
NC Aluminum Race Radiator ↗
Flyin' Miata· $549.00 USD
Single Pass Aluminum Race Radiator (ND) ↗Flyin' Miata· $549.00 USD
Gearbox & Drivetrain 3
- Ford C-4 automatic transmissionFord
Automatic gearbox paired with the V8, fitted with a 3500 stall converter
In the shops
BW-8 Automatic Transmission ↗Moss Motors – Triumph TR6/TR250· $0.00 USD
DG250 Automatic Transmission ↗Moss Motors – Triumph TR6/TR250· $0.00 USD
BW-35 Automatic Transmission ↗Moss Motors – Triumph TR6/TR250· $0.00 USD - 3500 stall torque converter
High-stall converter matched to the C-4 for drag use
In the shopsTorque Converter Cover ↗Motaclan Limited· £0.00 GBP
Torque Converter Assembly ↗Torque Converter Cover Nut ↗ - Ford 9 inch rear axleFord
Rear end fitted with 3.89 gears and a full spool for the drag application
Suspension & Steering 2
- Ladder bar rear suspension
Fitted to locate the rear axle for drag racing
In the shopsFront Suspension Tie Bar Rubber Bush ↗bpnorthwest.com· $1.72 USD - Coil-over shocks
Used at the rear as part of the suspension setup
Wheels & Tyres 1
- Weld Prostar wheelsWeld
Fitted front (15x3.5) and rear (15x12) for drag racing
Body & Trim 2
- 6 point rollcage
Installed for chassis stiffness and driver safety
- 2x3 square tube frame section
Added from the engine compartment rearward to strengthen the chassis
Photos
All 10 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
The build centres on a Ford 302 stroked to 349 cubic inches, fed by a Parker Funnel Web intake and an 830 cfm Holley carburettor. A solid flat tappet Comp cam with 0.592 inch lift on both sides works with MSD ignition to fire it. Cooling is handled by a Griffin aluminum radiator to Mustang specification.
Drivetrain
Power runs through a Ford C-4 automatic gearbox fitted with a 3500 rpm stall converter. Behind that sits a Ford 9 inch rear end running 3.89 gears and a full spool, giving the car a straightforward, strong setup suited to repeated hard launches.
Chassis and suspension
To handle the added power and abuse of drag racing, the TR7 was fitted with a 6 point rollcage and a 2x3 inch square tube frame section running from the engine bay rearward. The rear suspension uses ladder bars and coil-over shocks.
Wheels and finished result
The car rides on Weld Prostar wheels, 15x3.5 at the front and a wide 15x12 at the rear. Completed in 2004, the TR7 weighs 2500 lbs with the driver aboard and has run quarter mile times in the low 11 second range.
A summary in our own words. The full account, with all its detail, is the owner's: read it at britishv8.org ↗
Worth knowing
- A stroked small block with the right cam and carb combination can push a light TR7 into low 11 second quarter miles.
- A dedicated drag setup benefits from a full spool and low gearing (3.89) in a Ford 9 inch rear end.
- Adding a rollcage and a reinforced square tube subframe helps the chassis cope with V8 power and drag launches.
- A high stall converter (3500 rpm) paired with a C-4 automatic suits hard launches better than a stock converter.