Renault confirmed after testing at Barcelona that they would bring two 'B-spec' power units to the Principality after successful evaluations, but at the time did not confirm which drivers would benefit.
Red Bull have elected to hand their TAG Heuer-badged engine to Ricciardo, who currently sits fifth in the championship - one spot and 10 points ahead of new team mate Max Verstappen, who broke all manner of records when he won in his first race for the team last time out.
“The unit looked very promising when we first tried it, so I’m really looking forward to seeing how we get on with it here,” Ricciardo said.
Over at Renault it will be Magnussen - like Ricciardo ahead of his team mate in the championship standings - who receives the updated power unit.
Renault estimated their new engine could be worth anything up to half a second per lap, although they do not expect to see such gains in Monaco given the confines of the circuit.
Verstappen and Jolyon Palmer are set to use the upgraded power unit from Canada onwards.