Triumph TR6 Vehicle Information

Triumph TR6

Location of Serial Numbers
Before ordering any parts, it is essential that you have full details of the chassis number, engine number, body number, rear axle and gearbox numbers.

Triumph TR6 IllustrationA. The commission or chassis number on early TR6 models was mounted on plates affixed to the top of the inner left hand front wing. The plate included the commission number which could have a suffix “L” OR “U” (1971 on) for left hand drive models, and “O” for overdrive.

B. Later TR6 models had the commission plate attached to the left hand ‘B’ post, below the door shut plate.

C. Two plates attached to the bulkhead were body numbers. One was fitted by the manufacturers of the bodyshell, the other by Triumph. These numbers are not required when ordering replacement parts.

D. The engine number was stamped onto a lip at the rear of the left hand side of all engine blocks, just visible below the spark plug. The engine number is essential when ordering engine parts.

E. The gearbox number is stamped onto the casing just behind the clutch lever crosshaft box. On later USA models the number was stamped above the starter motor bulge on the right hand side of the gearbox casing. Use this number when ordering gearbox parts.

F. The rear axle number is located at the base of the axle housing, when viewed from beneath the car. Use this number when ordering axle parts.

IMPORTANT NOTE: Vehicle Commission Numbers & Component Serial Numbers. Wherever identification numbers are quoted in this catalogue (to help you to distinguish Factory changes/years), they relate to the Original Factory Specification or Component(s) when the vehicle was new and not subsequent or miscellaneous replacements.

Service Information

Original Settings and Standard Serial Numbers
Engine Settings
Firing Order (No. 1 at front) 1, 5, 3, 6, 2, 4
Spark Plug Gap 0.025"
Contact Breaker Gap 0.014" to 0.016"
Rotation (Distributor) Anti-Clockwise
Ignition Timing - Static 12° BTDC
Ignition Timing - Idel 4° ATDC
Idle Speed - PI 700 - 850 RPM
Idle Speed - Carb 800-850 RPM
Fast Idle Speed - PI 1300 - 1500 RPM
Fast Idle Speed - Carb 1100 - 1300 RPM
Valve Clearance (Cold) 0.010"
Capacities
Engine
Sump and oil filter 9 pints (5.10L)
Sump only 8 pints (4.54L)
Cooling System (inc heater) 11 pints (6.25L)
Fuel Tank (approx) 11 gallons (50L)
Gearbox
Non O/Drive 2 pints (1.13L)
With 'A' type O/Drive 3.5 pints (2.0L)
With 'J' type O/Drive 2.6 pints (1.5L)
Rear Axle 2.25 pints (1.27L)
Tyre Pressures (Standard Wheels/Tyres - Normal Driving)
Front (Cold) 22 PSi
Rear (Cold) 26 PSi


Vehicle Identification

  TR6 PI Models   TR6 Carburetter Models
1968 1969
Model Year
CP25156 First production car
(built 28th Nov 68)
1969
Model Year
CC25003 L First production car
(built 19th Sept 68)
CP25158 Last production car that year CC27383 L Last production car that year
CP25001 First car was probably a prototype CC25001 & CC25002 not yet found in
factory build records
CKD CP25002 to CP25145
were CKD
   
1969 1969
Model Year
CP25159 First production car
(built 2nd Jan 69)
1969
Model Year
CC27384 L First production car
(built 2nd Jan 69)
CP26998 Last production car
(built 10th Sept 68)
CC32142 L Last production car
(built 19th Dec 69)
1970
Model Year
CP50001 First production car
(built 1st Sept 69)
1970
Model Year
CC50001 L First production car
(built 22nd Nov 69)
CP50464 Last production car that year CC51032 L Last production car that year
CKD CP5001 to CP50436 believed to be CKD cars    
1970 1970
Model Year
CP50465 First production car
(built 1st Jan 70)
1970
Model Year
CC51033 L First production car
(built 1st Jan 70)
CP52785 Last production car that year CC60902 L Last production car that year
1971 1971
Model year
CP52786 First production car
(built 1st Jan 71)
1971
Model Year
CC60903 L First production car
(built 1st Jan 71)
CP54572 Last production car
(built 7th Sept 71)
CC67893 L Last production car
(built 20th Aug 71)
CKD CP54573 to CP54584
were CKD cars
1972
Model Year
CC75001 L First production car
(built 20th Aug 71)
1972
Model Year
CP75001 First production car
(built 27th Sept 71)
CC7881 Last production car that year
CP7544 Last production car that year    
1972 1972
Model Year
CP75455 First production car
(built 3rd Jan 72)
1972
Model Year
CC78813 U First production car
(built 3rd Jan 72)
CP77718 Last production car
(built 21st Sept 72)
CC85737 U Last production car
(built 5th Oct 72)
1973
Model Year
CR169 First production car
(built 15th Nov 72)
1973
Model Year
CF1 U First production car
(built 11th Sept 72)
CR664 Last production car that year CF4028 U Last production car that year
CKD CR1 to CR168
were CKD cars
   
1973 1973
Model Year
CR665 First production car
(built on 2nd Jan 73)
1973
Model Year
CF4029 U First production car
(built 2nd Jan 73)
CR2911 Last production car
(built 17th Oct 73)
CF17002 U Last production car that year
1974
Model Year
CR5049 First production car
(built 14th Sept 73)
     
CR5612 Last production car that year      
  CKD CR5001 to CR5048
were CKD cars
     
1974 1974
Model Year
CR5613 First production car
(built 1st Jan 74)
1974
Model Year
CF17002 U First production car
(built 2nd Jan 74)
CR6630 Last production car that year CF25777 U Last production car
(built 18th Sept 74)
1975 1974
Model Year
CR6631 First production car
(built 1st Jan 75)
1975
Model Year
CF27001 U First production car
(built 22nd Aug 74)
CR6701 Last production car
(built 7th Feb 75)
CF29580 U Last production car that year
      1976
Model Year
CF50001 U First production car
(built 29th Aug 75)
      CF52314 U Last production car that year
1976       1976
Model Year
CF52315 U First production car
(built 5th Jan 76)
      CF58328 U Last ever production TR6
(built 15th Jul 76)

Evolution of the TR Range

The TR6 was the last link of a long evolutionary trail that dated back to the early 1950's, and perhaps even earlier. The TR story started in 1952 when Harry Webster's design team, along with body designer Walter Belgrove, showed their concept of a new ‘Triumph Sports Car' at Earls Court. Public reaction proved positive and over the following winter Webster's team worked hard to develop a production model.

Based on the Standard Vanguard wet liner engine, a sturdy Flying Standard Nine chassis and front suspension from the old Triumph Mayflower, Belgrove's team introduced the TR2 to an excited public at Geneva. From here on the evolutionary process began that led to the TR5 and finally the TR6.

Following minor facelifts and engine alterations seen in the TR3 and TR3A models, the TR grew into a more sophisticated beast when, in 1961, Giovanni Micholotti styled the TR4. Under the body however, it was still essentially the original TR, though the evolutionary process was now well under way.

The 1965 TR4A may have looked the same as the TR4 but was transformed with a redeveloped chassis and independent rear suspension. In the US, the new "bell" chassis was modified lightly so that the older live rear axle could continue in use. It had been felt that US drivers would not be comfortable with the more sporting characteristics of the new irs axle!

Two years later, the TR5 and TR250 was introduced with its six cylinder 2.5 litre engine. Now much sought after, the TR5 (and the TR250 of America) gave a new lease of life to this enduring classic.

The TR5/250 didn't last long though. After only fifteen months the TR5 and TR250 were replaced by the TR6 in November 1968. Micholotti was unavailable to design the TR6 body, busy on a number of projects and so, after an exhaustive search, Karmann of West Germany were selected to produce designs. The new TR6 used the same chassis, inner shell, screen, and (if you look closely) even the same doors. Stylish and understated, losing none of the raw aggressiveness and purposeful design of the earlier TR models, the new model was another evolutionary step forward - retaining the best aspects of the classic TR.

Wider wheels were used on the new model while beneath the skin, the suspension geometry was revised and an anti-roll bar was added. In 1970 revised wheel trims were included, while inside the car a new steering wheel was fitted and seat designs were improved to protect against whiplash injuries.

1971 saw a new gearbox, taken from the new Triumph Stag. Being much stronger than the previous unit it was more able to deal with the powerful engine that it had been mated to. The old "A" type overdrive unit was replaced with the more durable "J" type, the only negative point being that it operated on third and forth gear only. Overdrive became standard fitment in 1974.

In 1973 a front spoiler was added, wheel trims revised, matt black wipers introduced - with revisions to instruments and switches. New external badging was provided. Wire wheels, rarely requested as an option, were deleted in the same year. Seats were revised again and, externally, new overriders were installed on USA models.

Throughout the development and production life of the TR6 the corporate owners of Triumph, British Leyland, were making changes affecting the whole organisation. Triumph had run its own, albeit small, competitions department until British Leyland gave responsibility for a competitions programme to Peter Browning of Abingdon's Competitions Department.

In the US, Kas Kastner headed up North American efforts, and a canny, clever man he was too, knowing all the wrinkles of the SCCA rule book inside out.

The SCCA, or more properly the Sports Car Club of America, was the premier American racing organisation. Kas' reputation for turning the TRs into rocket ships had suffered setbacks with the introduction of the TR5 which, with its bigger, difficult to tune engine, was put in a class with more predatory fish. However, following the introduction of the TR6 Kas discovered to his delight that a change in the rules meant that he could run the new TR6 with fuel injection. Better still he could run any sort of fuel injectors with trumpets.

With the original fuel injection system in place but disconnected, Kas ran a modified injector set up through the trumpets, blasting fuel straight in and giving the engines a massive 255 bhp. It provided a new lease of life on the tracks against competition such as Porche, and battled manfully on for a few more seasons to great success.

The last fuel injected TR6 left the Coventry factory in July 1975, the last Federal version a year later. During this time the new TR7 was introduced and the two models, radically different in every way, were manufactured side by side for a short while.

Some cars just refuse to lie down and the Triumph TR6 is no exception. In the late 1980's Britain's great export took on a star role in "Three Men and a Baby".

Triumph enthusiasts were buzzing with excitement when, in 1992, British Motor Heritage re-introduced the TR6 body shell. Undoubtably recognised as the last "macho" British sportscar, the new shells, all manufactured using original tooling and jigs, gave Triumph's classic a new lease of life.

Re-introducing the TR6 shells was the culmination of years of research and hard work, but on their own make up only part of an amazing story. More parts are available for the whole range of TR sports cars than ever before thanks to the unstinting efforts of enthusiasts around the world. Old tooling is continually being re-discovered and used again to produce obsolete parts, while reproduction components, often better than the originals (thanks to modern material use) are arriving on the scene everyday. Specialists around the world have bent all their thoughts and skills to keeping these cars on the road and thanks to their efforts the TR owner has back up and technical support that almost defies equal. It would be hard to imagine the owner of a TR ever having to scrap a car now.

The six cylinder TR engine

It's hard to believe that the six cylinder engine that powered the TR5, TR250 and TR6 had its humble beginnings in the 803cc Standard 8 of 1954. Harry Webster's 4 cylinder engine was used in the Triumph Herald, Spitfire and eventually even in the MG Midget, having grown into a 1500cc engine. Along the way, the engine gained two extra cylinders and, with a capacity of 1998cc, was used to power the Vanguard Six, Triumph 2000 and GT6 and, in reduced capacity initially, the Vitesse!

For TR use however, the engine needed even greater performance and though the rally engined Triumph 2000s were getting 150 bhp out of triple Weber carburated cars, this was at the cost of economy! The whole family of engines on which the TR engine was based used a stroke of 76mm. The only way forward was to increase the stroke to 95mm - flying in the face of modern engine design at the time. To do this, the block was extensively modified to take a new crankshaft. At the same time, the cylinder head was completely redeveloped.

With a slightly wild camshaft, the new fuel injected engine gave 150bhp. The carburetted "Federal" version offered 104bhp. The Lucas fuel injected cars were given an engine prefix of CP, the carburetted versions had a prefix CC. In 1973, with the introduction of a milder cam (to improve TR performance in heavy traffic), the prefixes changed from CP to CR and CC to CF.

The fuel injected cars maintained a compression ratio of 9.5:1, though the Federal cars began life with a ratio of 8.6:1, reducing to 7.75:1 in 1971 (coupled to new Stromberg 175 CDSE(2) carburetters) and then to 7.5:1 in 1973 (this time with Stromberg 175 SEV carburetters being fitted.

Exhaust and emission restrictions gradually stifled the performance of Federal/Californian cars eventually to TR4 standards. Even so sales of the cars continued alongside the newly introduced TR7.

Triumph TR6 Vehicle Information



Triumph TR6

Location of Serial Numbers
Before ordering any parts, it is essential that you have full details of the chassis number, engine number, body number, rear axle and gearbox numbers.

Triumph TR6 Illustration

A.
The commission or chassis number on early TR6 models was mounted on plates affixed to the top of the inner left hand front wing. The plate included the commission number which could have a suffix “L” OR “U” (1971 on) for left hand drive models, and “O” for overdrive.

B. Later TR6 models had the commission plate attached to the left hand ‘B’ post, below the door shut plate.

C. Two plates attached to the bulkhead were body numbers. One was fitted by the manufacturers of the bodyshell, the other by Triumph. These numbers are not required when ordering replacement parts.

D. The engine number was stamped onto a lip at the rear of the left hand side of all engine blocks, just visible below the spark plug. The engine number is essential when ordering engine parts.

E. The gearbox number is stamped onto the casing just behind the clutch lever crosshaft box. On later USA models the number was stamped above the starter motor bulge on the right hand side of the gearbox casing. Use this number when ordering gearbox parts.

F. The rear axle number is located at the base of the axle housing, when viewed from beneath the car. Use this number when ordering axle parts.

IMPORTANT NOTE: Vehicle Commission Numbers & Component Serial Numbers. Wherever identification numbers are quoted in this catalogue (to help you to distinguish Factory changes/years), they relate to the Original Factory Specification or Component(s) when the vehicle was new and not subsequent or miscellaneous replacements.

Service Information

Original Settings and Standard Serial Numbers
Engine Settings
Firing Order (No. 1 at front) 1, 5, 3, 6, 2, 4
Spark Plug Gap 0.025"
Contact Breaker Gap 0.014" to 0.016"
Rotation (Distributor) Anti-Clockwise
Ignition Timing - Static 12° BTDC
Ignition Timing - Idel 4° ATDC
Idle Speed - PI 700 - 850 RPM
Idle Speed - Carb 800-850 RPM
Fast Idle Speed - PI 1300 - 1500 RPM
Fast Idle Speed - Carb 1100 - 1300 RPM
Valve Clearance (Cold) 0.010"
Capacities
Engine
Sump and oil filter 9 pints (5.10L)
Sump only 8 pints (4.54L)
Cooling System (inc heater) 11 pints (6.25L)
Fuel Tank (approx) 11 gallons (50L)
Non O/Drive 2 pints (1.13L)
With 'A' type O/Drive 3.5 pints (2.0L)
With 'J' type O/Drive 2.6 pints (1.5L)
Rear Axle 2.25 pints (1.27L)
Tyre Pressures (Standard Wheels/Tyres - Normal Driving)
Front (Cold) 22 PSi
Rear (Cold) 26 PSi


Vehicle Identification

  TR6 PI Models   TR6 Carburetter Models
1968 1969
Model Year
CP25156 First production car
(built 28th Nov 68)
1969
Model Year
CC25003 L First production car
(built 19th Sept 68)
CP25158 Last production car that year CC27383 L Last production car that year
CP25001 First car was probably a prototype CC25001 & CC25002 not yet found in
factory build records
CKD CP25002 to CP25145
were CKD
   
1969 1969
Model Year
CP25159 First production car
(built 2nd Jan 69)
1969
Model Year
CC27384 L First production car
(built 2nd Jan 69)
CP26998 Last production car
(built 10th Sept 68)
CC32142 L Last production car
(built 19th Dec 69)
1970
Model Year
CP50001 First production car
(built 1st Sept 69)
1970
Model Year
CC50001 L First production car
(built 22nd Nov 69)
CP50464 Last production car that year CC51032 L Last production car that year
CKD CP5001 to CP50436 believed to be CKD cars    
1970 1970
Model Year
CP50465 First production car
(built 1st Jan 70)
1970
Model Year
CC51033 L First production car
(built 1st Jan 70)
CP52785 Last production car that year CC60902 L Last production car that year
1971 1971
Model year
CP52786 First production car
(built 1st Jan 71)
1971
Model Year
CC60903 L First production car
(built 1st Jan 71)
CP54572 Last production car
(built 7th Sept 71)
CC67893 L Last production car
(built 20th Aug 71)
CKD CP54573 to CP54584
were CKD cars
1972
Model Year
CC75001 L First production car
(built 20th Aug 71)
1972
Model Year
CP75001 First production car
(built 27th Sept 71)
CC7881 Last production car that year
CP7544 Last production car that year    
1972 1972
Model Year
CP75455 First production car
(built 3rd Jan 72)
1972
Model Year
CC78813 U First production car
(built 3rd Jan 72)
CP77718 Last production car
(built 21st Sept 72)
CC85737 U Last production car
(built 5th Oct 72)
1973
Model Year
CR169 First production car
(built 15th Nov 72)
1973
Model Year
CF1 U First production car
(built 11th Sept 72)
CR664 Last production car that year CF4028 U Last production car that year
CKD CR1 to CR168
were CKD cars
   
1973 1973
Model Year
CR665 First production car
(built on 2nd Jan 73)
1973
Model Year
CF4029 U First production car
(built 2nd Jan 73)
CR2911 Last production car
(built 17th Oct 73)
CF17002 U Last production car that year
1974
Model Year
CR5049 First production car
(built 14th Sept 73)
     
CR5612 Last production car that year      
  CKD CR5001 to CR5048
were CKD cars
     
1974 1974
Model Year
CR5613 First production car
(built 1st Jan 74)
1974
Model Year
CF17002 U First production car
(built 2nd Jan 74)
CR6630 Last production car that year CF25777 U Last production car
(built 18th Sept 74)
1975 1974
Model Year
CR6631 First production car
(built 1st Jan 75)
1975
Model Year
CF27001 U First production car
(built 22nd Aug 74)
CR6701 Last production car
(built 7th Feb 75)
CF29580 U Last production car that year
      1976
Model Year
CF50001 U First production car
(built 29th Aug 75)
      CF52314 U Last production car that year
1976       1976
Model Year
CF52315 U First production car
(built 5th Jan 76)
      CF58328 U Last ever production TR6
(built 15th Jul 76)

Evolution of the TR Range

The TR6 was the last link of a long evolutionary trail that dated back to the early 1950's, and perhaps even earlier. The TR story started in 1952 when Harry Webster's design team, along with body designer Walter Belgrove, showed their concept of a new ‘Triumph Sports Car' at Earls Court. Public reaction proved positive and over the following winter Webster's team worked hard to develop a production model.

Based on the Standard Vanguard wet liner engine, a sturdy Flying Standard Nine chassis and front suspension from the old Triumph Mayflower, Belgrove's team introduced the TR2 to an excited public at Geneva. From here on the evolutionary process began that led to the TR5 and finally the TR6.

Following minor facelifts and engine alterations seen in the TR3 and TR3A models, the TR grew into a more sophisticated beast when, in 1961, Giovanni Micholotti styled the TR4. Under the body however, it was still essentially the original TR, though the evolutionary process was now well under way.

The 1965 TR4A may have looked the same as the TR4 but was transformed with a redeveloped chassis and independent rear suspension. In the US, the new "bell" chassis was modified lightly so that the older live rear axle could continue in use. It had been felt that US drivers would not be comfortable with the more sporting characteristics of the new irs axle!

Two years later, the TR5 and TR250 was introduced with its six cylinder 2.5 litre engine. Now much sought after, the TR5 (and the TR250 of America) gave a new lease of life to this enduring classic.

The TR5/250 didn't last long though. After only fifteen months the TR5 and TR250 were replaced by the TR6 in November 1968. Micholotti was unavailable to design the TR6 body, busy on a number of projects and so, after an exhaustive search, Karmann of West Germany were selected to produce designs. The new TR6 used the same chassis, inner shell, screen, and (if you look closely) even the same doors. Stylish and understated, losing none of the raw aggressiveness and purposeful design of the earlier TR models, the new model was another evolutionary step forward - retaining the best aspects of the classic TR.

Wider wheels were used on the new model while beneath the skin, the suspension geometry was revised and an anti-roll bar was added. In 1970 revised wheel trims were included, while inside the car a new steering wheel was fitted and seat designs were improved to protect against whiplash injuries.

1971 saw a new gearbox, taken from the new Triumph Stag. Being much stronger than the previous unit it was more able to deal with the powerful engine that it had been mated to. The old "A" type overdrive unit was replaced with the more durable "J" type, the only negative point being that it operated on third and forth gear only. Overdrive became standard fitment in 1974.

In 1973 a front spoiler was added, wheel trims revised, matt black wipers introduced - with revisions to instruments and switches. New external badging was provided. Wire wheels, rarely requested as an option, were deleted in the same year. Seats were revised again and, externally, new overriders were installed on USA models.

Throughout the development and production life of the TR6 the corporate owners of Triumph, British Leyland, were making changes affecting the whole organisation. Triumph had run its own, albeit small, competitions department until British Leyland gave responsibility for a competitions programme to Peter Browning of Abingdon's Competitions Department.

In the US, Kas Kastner headed up North American efforts, and a canny, clever man he was too, knowing all the wrinkles of the SCCA rule book inside out.

The SCCA, or more properly the Sports Car Club of America, was the premier American racing organisation. Kas' reputation for turning the TRs into rocket ships had suffered setbacks with the introduction of the TR5 which, with its bigger, difficult to tune engine, was put in a class with more predatory fish. However, following the introduction of the TR6 Kas discovered to his delight that a change in the rules meant that he could run the new TR6 with fuel injection. Better still he could run any sort of fuel injectors with trumpets.

With the original fuel injection system in place but disconnected, Kas ran a modified injector set up through the trumpets, blasting fuel straight in and giving the engines a massive 255 bhp. It provided a new lease of life on the tracks against competition such as Porche, and battled manfully on for a few more seasons to great success.

The last fuel injected TR6 left the Coventry factory in July 1975, the last Federal version a year later. During this time the new TR7 was introduced and the two models, radically different in every way, were manufactured side by side for a short while.

Some cars just refuse to lie down and the Triumph TR6 is no exception. In the late 1980's Britain's great export took on a star role in "Three Men and a Baby".

Triumph enthusiasts were buzzing with excitement when, in 1992, British Motor Heritage re-introduced the TR6 body shell. Undoubtably recognised as the last "macho" British sportscar, the new shells, all manufactured using original tooling and jigs, gave Triumph's classic a new lease of life.

Re-introducing the TR6 shells was the culmination of years of research and hard work, but on their own make up only part of an amazing story. More parts are available for the whole range of TR sports cars than ever before thanks to the unstinting efforts of enthusiasts around the world. Old tooling is continually being re-discovered and used again to produce obsolete parts, while reproduction components, often better than the originals (thanks to modern material use) are arriving on the scene everyday. Specialists around the world have bent all their thoughts and skills to keeping these cars on the road and thanks to their efforts the TR owner has back up and technical support that almost defies equal. It would be hard to imagine the owner of a TR ever having to scrap a car now.

The six cylinder TR engine

It's hard to believe that the six cylinder engine that powered the TR5, TR250 and TR6 had its humble beginnings in the 803cc Standard 8 of 1954. Harry Webster's 4 cylinder engine was used in the Triumph Herald, Spitfire and eventually even in the MG Midget, having grown into a 1500cc engine. Along the way, the engine gained two extra cylinders and, with a capacity of 1998cc, was used to power the Vanguard Six, Triumph 2000 and GT6 and, in reduced capacity initially, the Vitesse!

For TR use however, the engine needed even greater performance and though the rally engined Triumph 2000s were getting 150 bhp out of triple Weber carburated cars, this was at the cost of economy! The whole family of engines on which the TR engine was based used a stroke of 76mm. The only way forward was to increase the stroke to 95mm - flying in the face of modern engine design at the time. To do this, the block was extensively modified to take a new crankshaft. At the same time, the cylinder head was completely redeveloped.

With a slightly wild camshaft, the new fuel injected engine gave 150bhp. The carburetted "Federal" version offered 104bhp. The Lucas fuel injected cars were given an engine prefix of CP, the carburetted versions had a prefix CC. In 1973, with the introduction of a milder cam (to improve TR performance in heavy traffic), the prefixes changed from CP to CR and CC to CF.

The fuel injected cars maintained a compression ratio of 9.5:1, though the Federal cars began life with a ratio of 8.6:1, reducing to 7.75:1 in 1971 (coupled to new Stromberg 175 CDSE(2) carburetters) and then to 7.5:1 in 1973 (this time with Stromberg 175 SEV carburetters being fitted.

Exhaust and emission restrictions gradually stifled the performance of Federal/Californian cars eventually to TR4 standards. Even so sales of the cars continued alongside the newly introduced TR7.