Mattia Binotto says it will take Ferrari "two or three upgrades" before the Italian team can take on Mercedes at every track.
Notwithstanding Sebastian Vettel's controversial penalty, the German driver beat Lewis Hamilton on the track in Canada.
But boss Binotto says that was circuit-specific.
"As a circuit, Paul Ricard should be more difficult for us," he told the Italian broadcaster Rai. "It's more like Barcelona than Montreal."
And so he said Maranello is working flat-out to alter the 'concept' of the Ferrari car.
"Regarding the tyres, obviously we cannot change that. What we can do is change the concept of our car," said Binotto.
"That means more downforce and drag. And you cannot correct that in a day.
"The process will take several weeks, because we have to make sure that any changes to our aerodynamics go in the right direction.
"It will take two or three upgrades before we're able to challenge Mercedes everywhere."
And so until those upgrades succeed, Binotto admitted the world championship is "not the question I'm asking right now".
"The priority is that we recognise the problem correctly and react to it in the best way so that we can regain our strength as soon as possible."
