For the 1970 season following Matra's merger with Simca, Tyrrell were asked by Matra to use their V12 rather than the Cosworth.
Simca was a subsidiary of the American company Chrysler, a rival of Ford.

Stewart tested the Matra V12 and found it inferior to the DFV.
As a large part of the Tyrrell budget was provided by Ford, and another significant element came from French state-owned petroleum company Elf, which had an agreement with Renault that precluded supporting a Simca partner, Ken Tyrrell had little alternative but to buy a March 701 chassis as interim solution while developing his own car in secret.

Tyrrell was still sponsored by French fuel company Elf, and Tyrrell would retain the traditional French blue racing colours for most of the rest of its existence.
Tyrrell and Stewart ran the March-Fords throughout 1970 with mixed success, while Derek Gardner worked on the first in-house Tyrrell Grand Prix car at the woodshed in Ockham, Surrey.

The Tyrrell 001, which bore much resemblance to the MS80, emerged at the end of 1970.
It earned Stewart a pole position in the Canadian GP but suffered mechanical failures in all of its 3 race starts.
The nearly identical Tyrrell 003 won both Drivers' and Constructors' Championships in 1971, with strong driving from Jackie Stewart and François Cevert.
 Stewart's 1972 challenge was ruined by a stomach ulcer, but he returned to full fitness in 1973.
 He and Cevert finishing 1st and 4th in the Championship.
 Tragedy struck on 6 October 1973, as Cevert was killed in practice for the US Grand Prix at Watkins Glen.
 Stewart, who was to retire at the end of the season, and Tyrrell immediately stood down, effectively handing the Constructors' title to Lotus.
At the end of the season Stewart made public his decision to retire, a decision that was already made before the US Grand Prix.
Without their star driver or his skilled French protégé aboard, Tyrrell were never serious World Championship contenders again.

Despite this, the team remained a force throughout the 1970s, winning races with Jody Scheckter and Patrick Depailler.
Most notable of these was Scheckter's triumph at the 1976 Swedish Grand Prix, giving Tyrrell a 1–2 finish driving the distinctive Derek Gardner designed Tyrrell P34 car.
The P34 was the first (and only) successful six-wheeler F1 car, which replaced the conventional front wheels with smaller wheels mounted in banks of two on either side of the car.
The design was abandoned after Goodyear refused to develop the small tyres needed for the car as they were too busy fighting the other tyre manufacturers in Formula One.

Ken Tyrrell had been spending a lot of his own money running his team, but in the summer of 1979 he finally found a sponsor: Italian appliance manufacturing group Candy put up the money to run the 009, fielded by Jarier and Pironi.
For the 1970 season following Matra's merger with Simca, Tyrrell were asked by Matra to use their V12 rather than the Cosworth. Simca was a subsidiary of the American company Chrysler, a rival of Ford. 
Stewart tested the Matra V12 and found it inferior to the DFV. As a large part of the Tyrrell budget was provided by Ford, and another significant element came from French state-owned petroleum company Elf, which had an agreement with Renault that precluded supporting a Simca partner, Ken Tyrrell had little alternative but to buy a March 701 chassis as interim solution while developing his own car in secret.
Tyrrell was still sponsored by French fuel company Elf, and Tyrrell would retain the traditional French blue racing colours for most of the rest of its existence. Tyrrell and Stewart ran the March-Fords throughout 1970 with mixed success, while Derek Gardner worked on the first in-house Tyrrell Grand Prix car at the woodshed in Ockham, Surrey.
The Tyrrell 001, which bore much resemblance to the MS80, emerged at the end of 1970. It earned Stewart a pole position in the Canadian GP but suffered mechanical failures in all of its 3 race starts. The nearly identical Tyrrell 003 won both Drivers' and Constructors' Championships in 1971, with strong driving from Jackie Stewart and François Cevert.  Stewart's 1972 challenge was ruined by a stomach ulcer, but he returned to full fitness in 1973.  He and Cevert finishing 1st and 4th in the Championship.  Tragedy struck on 6 October 1973, as Cevert was killed in practice for the US Grand Prix at Watkins Glen.  Stewart, who was to retire at the end of the season, and Tyrrell immediately stood down, effectively handing the Constructors' title to Lotus. At the end of the season Stewart made public his decision to retire, a decision that was already made before the US Grand Prix. Without their star driver or his skilled French protégé aboard, Tyrrell were never serious World Championship contenders again.
Despite this, the team remained a force throughout the 1970s, winning races with Jody Scheckter and Patrick Depailler. Most notable of these was Scheckter's triumph at the 1976 Swedish Grand Prix, giving Tyrrell a 1–2 finish driving the distinctive Derek Gardner designed Tyrrell P34 car. The P34 was the first (and only) successful six-wheeler F1 car, which replaced the conventional front wheels with smaller wheels mounted in banks of two on either side of the car. The design was abandoned after Goodyear refused to develop the small tyres needed for the car as they were too busy fighting the other tyre manufacturers in Formula One.
Ken Tyrrell had been spending a lot of his own money running his team, but in the summer of 1979 he finally found a sponsor: Italian appliance manufacturing group Candy put up the money to run the 009, fielded by Jarier and Pironi.
Tyrrell Racing