Zak Brown says the noises being made by Renault ahead of the 2019 season are also "encouraging" for McLaren.
McLaren, now a Renault customer, struggled even after dumping Honda ahead of the 2018 season.
But team boss Brown says what he is hearing and seeing from Renault for 2019 is "quite encouraging".
"We are aware of the comments that Renault has made, and they have shared with us the details of what they have achieved," he is quoted by Spain's Marca.
"We are still new in this relationship but Renault is saying different things than it did last year. They maintained their position on where the engine is and what deficit it has, so based on that we have found that they are very honest in their communication.
"So it's encouraging that they are being as positive as they are," Brown said.
He said McLaren is also looking in better shape for 2019.
"In the second year with Renault, I think we've done a better job in relation to the power unit," said Brown.
"When we made the decision to change to Renault it was a bit late, and then we had some reliability problems because we did not know the power unit as we do now."
Daniel Ricciardo, the new works Renault driver, is also positive. The team he has fled, Red Bull, has switched from Renault to works Honda power for 2019.
"On the one hand, Honda is a new hope for the team, but on the other it is an unknown in many respects," he is quoted by Spain's Marca.
