With the break in Grand Prix racing from November, 1969, to March, 1970, all the teams, and some new ones, made remarkable efforts to be ready for the new season well on time. The result was that of the 23 cars that should have assembled for practice, 15 of them were about to be driven in their first competition.
In addition there were a remarkable number of first occasions as well, such as the appearance of the March cars and teams, the flat 12-cylinder Ferrari engine, the new Matras, McLarens, BRMs, Brabhams and the De Tomaso. New drivers and new driver/team combinations were rife, such as Ickx with Ferrari, Hill with Rob Walker, Surtees with his own team, Stommelen in a Formula One car for the first time, and Amon and Surtees experiencing Cosworth V8 power after years of sitting in front of V12-cylinder engines. From the first pit, occupied by Stewart and the Tyrrell March team, to the last pit occupied by Siffert and one of the STP-March cars, there was enormous activity.
There was only one absentee when practice began promptly at 2:30pm on Wednesday, March 4th, and that was Andretti and the STP Oil-Treatment Special (Or March 701/3 by any other name) for the Italian-born American had overcooked things the day before in an unofficial practice session and bent the rear end rather badly.