McLaren team boss and outgoing Formula One Teams' Association chairman Martin Whitmarsh says retaining Formula 1's current V8 engines alongside the 2014 V6 turbos in an equivalency formula would be an 'unattractive' option for the sport.
F1 will switch to new generation engines after next season, but there have been concerns that there might not be enough of the new V6s to supply the whole field, or that the costs will be too great for smaller teams.
AUTOSPORT understands that there have been tentative discussions about the possibility of allowing teams to continue using V8s as a back-up option, but this has so far found little favour - and Whitmarsh played it down.
"It's feasible," he said. "I don't think it's an attractive thing to do, personally. Equivalence formulas, we have had it before, we had it in '88, we had turbos and normally aspirateds when we were coming the other way. It wasn't such a bad memory for McLaren, but it wasn't an attractive formula."
Whitmarsh underlined that if V8s were kept on, the rules would have to be balanced in the V6s' favour.
"I think you'd have to arrange, if you did it, such that the new turbo engines have advantage over normally aspirated, so you're creating a two-tier championship, which is I think not an attractive thing to have," he said.
When F1 last changed engine regulations in 2006, Toro Rosso was given a temporary dispensation to continue running restricted versions of the previous V10 engines as the rest of the field switched to the new V8s.