Build catalogue
Jay Smith's 1963 TR4 Ford 302 V8 Conversion
britishv8.orgBritish V8 Newsletter, Volume X Issue 3, September 2002 (updated June 27, 2013)
Photo: britishv8.orgA 1963 Triumph TR4 converted to a Ford 302 V8 on a junkyard budget
Jay Smith swapped his TR4's four-cylinder for a low-mileage 1988 Ford Mustang GT 302, sourcing most parts secondhand to keep costs down. The write-up covers the steering and exhaust headaches that came with fitting a wider, longer V8, plus the driveline and suspension changes needed to make it work. It is a useful read for anyone weighing up a low-budget V8 conversion in a similar chassis.
Specs
As the owner states it.
- Engine
- 1988 Ford Mustang GT 302ci (5.0L) V8, Weiand aluminum intake, Holley 600cfm carburetor, MSD6A ignition, 125hp NOS nitrous system
- Exhaust
- Summit block hugger headers, 2" generic turbo mufflers, no crossover pipe yet
- Cooling
- Bronco radiator, aluminum Weiand water pump, GM electric puller fan
- Transmission
- Ford T5 5-speed, converted from hydraulic to cable clutch using a 1976 Mustang Cobra cable
- Rear axle
- Stock TR4 for now, with a limited-slip Ford unit awaiting installation
- Frame
- Cross-members modified/relocated for the engine and transmission
- Suspension
- Stock except for stiffer front springs and shocks
- Brakes
- Toyota 4-pot calipers in front, stock rear
- Wheels
- Triumph TR6 steel disc 15x6 wheels
- Tyres
- Yokohama AVS ES100 205/60R15
- Body
- Kept stock in appearance, a requirement of the conversion
- Electrical
- Autometer Pro-Comp gauges, Subaru 100-amp 1-wire alternator, Ford starter
- Completion
- July 1996, at a cost of $2,500
- Miles driven
- Over 6000 miles as of September 2002
- Performance
- Best 1/4 mile 13.7s at 105mph; driven to 124mph
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 3
- 1988 Ford Mustang GT 302ci (5.0L) V8 engineFord
Low-mileage (20,000 mile) donor engine used for the conversion
- Weiand aluminum intake manifoldWeiand
Fitted to the 302 V8
- 125hp NOS nitrous systemNOS
Fitted for extra power, usable only from mid third gear, not yet used at the track
Fuel & Ignition 4
- Holley 600cfm carburetorHolley
Carburetor fitted to the V8
- MSD6A capacitive discharge ignitionMSD
Ignition system fitted to the V8
- Accel 8.8 Silicone Plus spark plug wiresAccel
Spark plug wires fitted to the V8
- Marshall Shock Proof fuel pressure gauge (0-15psi)Marshall
Used to monitor fuel pressure
Cooling 3
- Bronco radiator
Fitted for cooling the V8 conversion
- Weiand aluminum water pumpWeiand
Fitted to the V8 for cooling
- GM electric fanGM
Fitted in a puller arrangement
Gearbox & Drivetrain 3
- Ford T5 5-speed transmissionFord
Replaced original gearbox to handle V8 power
- 1976 Mustang Cobra clutch cableFord (Mustang Cobra)
New cable used to convert clutch actuation from hydraulic to cable, connected via original clutch master cylinder lever
- Limited-slip Ford differentialFord
Held in reserve to install once the stock TR4 rear end fails
Suspension & Steering 1
- High-performance front springs and shocks
Replaced stock front springs/shocks for stiffer handling
Brakes 1
- Toyota 4-pot front calipersToyota
Fitted to the front brakes
Wheels & Tyres 2
- Triumph TR6 steel disc 15x6 wheelsTriumph
Fitted in place of original TR4 wheels
- Yokohama AVS ES100 205/60R15 tyresYokohama
Fitted on the TR6 wheels
Electrical 3
- Autometer Pro-Comp gaugesAutometer
Fitted in the dashboard to monitor engine
- Subaru 100-amp 1-wire alternatorSubaru
Fitted to supply the V8 electrical system
- Ford starterFord
Fitted to start the 302 V8
Other 2
- Summit block hugger headersSummit
Exhaust headers fitted to clear the chassis
- 2" generic turbo mufflers
Fitted as part of the exhaust, no crossover pipe yet
Photos
All 36 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
Starting the swap
Jay began the conversion in January 1996 and finished by July, working in spurts as time allowed over about six months. He aimed for a low-budget build, sourcing as many parts as possible from the local junkyard. The donor engine was a stock 1988 5.0L from a Mustang GT with only 20,000 miles on it.
Fitting the engine
The V8 fit the TR4 engine bay reasonably well and weighed only slightly more than the original four-cylinder, keeping weight distribution good. Cooling was handled with a Bronco radiator, an aluminum Weiand water pump and a GM electric puller fan.
Steering and exhaust troubles
The steering column needed rerouting around the wider V8, and the longer engine put the steering rack in the way. Rather than cut the firewall, Jay moved the rack forward a few inches, which caused poor steering and bump-steer that took considerable trial and error to sort out.
Suspension and driveline
New bushings went in along with high-performance front springs and shocks to replace the stock units. The transmission became a Ford T5 five-speed, converted from hydraulic to cable clutch actuation using a new 1976 Mustang Cobra cable connected via the original clutch master cylinder lever.
Rear axle and brakes
The rear end remains the stock TR4 single-trac unit, which has survived because the car cannot put all its power down cleanly; hard throttle spins the right rear tire. A limited-slip Ford differential is on hand to install when the stock unit eventually fails. Toyota 4-pot calipers were added up front.
Driving it
The finished car handles well and has plenty of torque and horsepower, running a best of 13.7 seconds at 105mph in the quarter mile while still spinning a tire. It has also been driven to 124mph. A 125hp nitrous system is fitted but not yet used at the track since it can only be engaged from mid third gear.
A summary in our own words. The full account, with all its detail, is the owner's: read it at britishv8.org ↗
Worth knowing
- Expect steering rack and column clearance problems when fitting a wider, longer V8, and budget extra time to sort out bump-steer.
- A junkyard-sourced, low-mileage donor V8 can keep costs down while still giving good performance.
- Route the exhaust through the frame from the start to avoid clearance issues, rather than leaving it as an afterthought.
- A stock rear differential may hold up fine if the car is driven mostly on the street rather than raced hard.
- A cable clutch conversion using a donor car's cable and the original master cylinder lever can work reliably even if it looks improvised.