Cowell would be an ideal candidate to run the project given his experience in overseeing the most dominant era in Formula 1 history as the former head of Mercedes High Performance Powertrains prior to his departure on July 1 last year.
Cowell announced at the time he would be seeking "a new engineering business challenge".
Asked about the possibility of recruiting Cowell, Horner said: “Andy Cowell, what he has achieved in the recent 10 years of the sport has been mightily impressive and he was obviously a lynchpin of what Mercedes and HPP have delivered.
"He has obviously chosen to pursue other activities outside of Formula 1 but, of course, as far as engines are concerned, he has been the guy that has delivered year-on-year. My understanding is his interests currently lie outside of Formula 1.”
Another high-profile name to be linked is that of current Ilmor Engineering technical director Mario Illien, who has been with a company he founded with Roger Penske
and Paul Morgan since 1984.
Horner has not ruled out utilising the services of Ilmor in the future, particularly with regard to the introduction of new engine regulations in 2025.
"Obviously, Mario and Honda have their own relationship and Ilmor is a proven company," added Horner.
"There are no plans to utilise the services of Ilmor at this point in time but you could potentially see the attraction of drawing on the knowledge and know-how of companies like that in the future at some point with the new regulations.
“But there have been no discussions. They have an exclusive contract with Honda which is very much their business.”
With what he describes as "a clean sheet of paper" on the recruitment side, Horner recognises there are numerous options.
"We will be appointing various roles, whether from a technical director, operating director, managing director – we have candidates in mind for each of those roles," said Horner.
“We get some very skilled people that will transfer as part of the agreement with Honda so we need to establish initially what we need, who we need, who is available.
“Formula 1 is a people business and whether that is chassis or engine, it’s a matter of accumulating the right people, getting them to work together as a team and empowering them.
"The powertrain side of the business will be no different to the chassis side in that respect.”
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