Williams technical director Sam Michael is confident Cosworth will produce a competitive engine when it returns to Formula 1 next season.
The team from Grove will use Cosworth power units beginning next year, having used Toyota engines for the past three seasons.
Although Cosworth has been away from Formula 1 for three years, Michael told AUTOSPORT he is cautiously optimistic that the Northampton, UK-based manufacturer will supply his team with a strong engine.
"We won't know that until we get it on the track," Michael said when asked if the Cosworth was a winning engine. "Our target is always to be at the front and, with the grid being so tight now, it's even more realistic to have that as a target as the regulations have closed everything up so much.
"Finding one or two tenths from aerodynamics or some other gain can put you in with a shout of winning races. That's why there have been so many winners this year. Cosworth are going to do a good job."
Williams last used Cosworth power units in 2006 before moving to Toyota, and the team is now going the other way. Despite that, Michael reckons it would not have been the best idea to stick with Cosworth all this time.
"The sport has changed massively since 2006," he said. "If you look back from the early 2000s to the last 18 months, it has been manufacturer dominated – but that's shifting significantly. There were different reasons for not being with Cosworth back then. But you can also ask if the decision we made was correct. We don't know, because history sets itself and that's it.
"If we had continued with Cosworth back then, maybe it wouldn't have been the best thing. That's the great thing about F1 – it keeps evolving. It's a process of change right now, and that has led things back to an independent engineering group being the best thing for Williams.
"Cosworth has got two big hurdles. Fuel consumption is critical with no refueling, and their target for the winter is to improve that. The other is reliability. Everyone has accumulated three years of running on their engines while Cosworth has been out and gained thousands of kilometers of knowledge."