Toro Rosso look to be a step closer to running 2015-spec Ferrari power units next season, after Formula One racing’s governing body, the FIA, cleared the way for teams to use previous year’s engines from 2016.
Current regulations do not permit manufacturer's to supply two different specifications of power unit over a single season, but Ferrari have now been given dispensation to supply a fourth customer team with year-old engines.
Toro Rosso have been in talks with Ferrari regarding such a deal for several months, with team principal Franz Tost telling Formula1.com in October that his outfit would accept a 2015-spec power unit from the Scuderia.
A statement released from Wednesday's Paris meeting of governing body the FIA's World Motor Sport Council read: "Power Units homologated in previous seasons may now be re-homologated. Previously no manufacturer could supply more than one specification of PU.
"The World Motor Sport Council was also advised that the FIA had agreed for Ferrari to supply a fourth customer team with a 2015-specification Power Unit in 2016."
Toro Rosso previously worked with Ferrari from 2007-13, before switching to Renault engines to mirror sister team Red Bull. The latter squad are yet to reach a formal resolution to their own power-unit supply uncertainty for 2016.