McLaren racing director Eric Boullier is confident the Woking-based outfit would have ended its four-year winless streak during the 2016 Formula One season if the MP4-31 chassis been fitted with the best engine in the field.
The two partners, who had enjoyed four consecutive championship doubles in 1988-1991, endured a torrid reunion amid poor engine performance and reliability.
Although Honda made significant progress in 2016, McLaren still had to settle for sixth in the Constructors’ championship with a best result of fifth for Fernando Alonso in Monaco and Austin.
“If we had the best engine this year, we would have won races," Boullier told Autosport.
“We know, the GPS traces tell us. There is room for improvement everywhere with Honda. It also drives your chassis development. Everything is connected.
“You can't make a car too draggy if you don't have enough power deployment because you lose time. You have to balance all the time. We work as one team with Honda to achieve what we want.”
The Frenchman also calls for patience and takes confidence from Renault’s steady improvement on its own 1.6-litre V6 turbocharged power unit, as well as the removal of the engine development token system.
“The gap has closed. But to get where Mercedes is, you can't just copy and paste.
“You can't do it in three months or six months but in a few years. It took Renault time and still today, they are not on top of the game.”
Mercedes' works team has won 51 out of 59 grands prix since 2014 and the start of the latest turbo era. McLaren's most recent victory streches back to a Jenson Button win at the 2012 Brazilian Grand Prix.