Both Toyotas will be slowed by more than three seconds per lap when the FIA World Endurance Championship resumes next month at Spa.
In the latest LMP1 success handicap bulletin issued by the WEC confirms the points-leading #7 Toyota TS050 Hybrid of Mike Conway, Jose Maria Lopez and Kamui Kobayashi will be penalised by 3.52s a lap for the Spa race on 15 August.
The sister #8 car shared by Sebastien Buemi, Kazuki Nakajima and Brendon Hartley meanwhile will be slowed by 3.08s a lap, due to the five-point difference in the standings.
These figures represent the same penalties that the Toyotas would have been given for the 1000 Miles of Sebring in March, had it not been cancelled amid the COVID-19 pandemic, albeit adjusted for track length.
For the Sebring race, the Japanese marque's cars would have been slowed by 3.02s and 2.77s a lap respectively, as the Florida track is slightly shorter than the 4.352 mile Spa layout.
The #1 Rebellion R-13, which won the most recent WEC race at the Circuit of the Americas in February, will be slowed by 1.58s a lap. It will run at 877kg, an increase of 30kg from COTA.
Both Toyotas are already running at their maximum weight of 932kg.
ByKolles, which is returning to the series with its ENSO CLM P1/01 design for the first time since last year's Le Mans 24 Hours, has been given an identical penalty to Rebellion, and its Gibson-powered contender will therefore also run at 877kg.
DTM champion Bruno Spengler will make his LMP1 debut with the team, and will be joined by team regulars Tom Dillmann and Oliver Webb, whose return was announced this week.
Ginetta is skipping the Spa race as it winds down its factory WEC involvement, but had the G60-LT-P1 been present it would have run penalty-free at a weight of 833kg.
Ginetta boss Lawrence Tomlinson told Autosport last week that the "ship has sailed" on continuing its factory involvement in 2021, when LMP1 cars will be allowed to compete against the new breed of LM Hypercars.