The Automobile Club de l'Ouest has revealed details of the new LMP2 regulations for 2017.
The ACO also confirmed a tender process for four constructors to supply chassis for the new-look class.
Motorsport.com understands the selected car builders are expected to be announced in July.
The ACO's Sporting Director, Vincent Beaumesnil said of the moves: "It is a major project and we have been working on it for a long time on this.
"The ACO, FIA and IMSA have worked together on the new regulations and we wanted to control costs and have a more economical model. The regulations will be globally unified."
Cars will be grandfathered over for the 2017 WEC season but new cars will only be eligible from 2018 onwards. The ELMS will accept entries of older cars until the end of the 2018 season.
The LMP2 cars will be homologated for four years and there will be no new models allowed for four seasons.
The ACO believes that costs will not increase, as operating costs are estimated be lowered. Estimations indicate a current working WEC budget of 3.2m euros. The aim is to reduce budgets by 20 per cent and get back to 2012 levels.
The new LMP2 chassis will be dimensionally smaller as per the current LMP1 cars. Zylon panels will be utilised in the cars to improve safety.
The new-look LMP2 cars will have a single engine supplier. The rules makers have been working with 21 engine manufacturers and want to reduce costs with the single engine, which will be rented by the teams.
New plans met with mixed reception
The new structure for the LMP2 class has been met with a mixed reaction from existing teams.
Some see the steps as a commercial long-term necessity, while others see the measures as diluting of LMP2's USP with a narrower choice of hardware, while others see the moves as unnecessary meddling with a successful and proven category.
Speaking to Motorsport.com earlier in the week, Greaves Motorsport team principal Tim Greaves said: "I am actually more pessimistic rather than optimistic' for the future of the category," he said.
"I actually understand and get what the FIA and ACO want to do and achieve with LMP2 but the rules are already in place to control the number of manufacturers today," continued Greaves.
"It specifically says that a manufacturer must produce six cars but it has never been implemented. If they are implemented properly then there is not a reason to make such a sweeping change."
"The reality is that it is highly likely only one of the four chosen manufacturers will get orders," continued Greaves. "I call it the 'Dallara-effect', which is what happened in single-seater racing over the last twenty years.
"Naturally one package will be quicker than the other and that will be found out quickly. Then what happens to the others? All of a sudden it becomes a one-make class. That is how I think it could play out in LMP2."