Craig Pollock is pushing ahead with his new venture Pure's plans to supply engines to Formula One teams.
The BAR team founder and former manager of Jacques Villeneuve announced in May that Propulsion Universelle et Recuperation d'Energie is designing a four-cylinder engine for the FIA's confirmed regulations for 2013.
But the governing body has now agreed with the F1 teams and existing engine makers to scrap the four-cylinder plans in favour of an all-new turbo V6 rules compromise for 2014.
Pollock told Dutch website gpupdate.net that the u-turn has set back Pure's progress by "about a month".
"We already started to work on the V6 engine when we realised it was going to happen, which was probably about ten days ago," he said last Friday.
"We will obviously be able to use certain technologies that we have developed from the four-cylinder and put it into the six-cylinder."
I don't think it has done the sport an awful lot of good
Pollock admits he is unhappy the rules have changed but scotched any suggestion Pure might have to scrap its plans to enter Formula One.
"Well it's not a case of we will (build a V6), we are," he said.
Pollock said he will be present for an FIA meeting about engines at Silverstone on Friday, where he is unlikely to mince his words.
"I'm very disappointed," he admitted. "I don't think it has done the sport an awful lot of good, I think yet again it shows huge weaknesses."