The Anglo-Swiss Rebellion Racing team is switching engine supplier for its 2015 LMP1 campaign in the World Endurance Championship.
Rebellion, which has used a normally-aspirated Toyota V8 for the past four seasons, has confirmed that it has decided against continuing with the Japanese manufacturer, but has yet to disclose the identity of the engine that will power its ORECA-built R-One chassis this season.
Team manager Bart Hayden told AUTOSPORT: "The decision to change has been made, but I can't go into detail.
"All I can say is that when we looked at the marketplace, we were surprised at the number of options.
"There is Judd with a V8 or a V10, the AER turbo V6 and the V8 developed by Neil Brown [based on the Audi DTM V8], as well as options from Honda Performance Development and Cosworth."
Hayden stated that the engine supplier would not necessarily be revealed when the entry lists for the WEC and the Le Mans 24 Hours are published next Thursday.
Rebellion will be making two full-season entries for the WEC, Hayden disclosed, but the engine switch could force the team to miss the season opener at Silverstone in April.
"It will be business as usual for Rebellion with two full entries if we are accepted, but it is still too early to say if we will be at Silverstone," he said.
Hayden revealed that ORECA would lead the design of the engine installation for the R-One.
He stressed that there was no major dissatisfaction with the Toyota engine, but he explained that the team had opted to look elsewhere because the 3.4-litre V8s were only available until the end of 2015.
"That prompted us to look at our longer-term future and ask the question, should we make the change earlier?" he said.
Rebellion is expecting to go into the new season with a largely-unchanged driver line-up.
"I don't think there will be much of the way of change, but Nissan has yet to make it announcements and I don't know if any of our guys have been in last-minute negotiations with them," said Hayden.
Rebellion's two entries in 2014 were driven by Nick Heidfeld, Nicolas Prost, Mathias Beche and Andre Belicchi, Fabio Leimer and Dominik Kraihamer.