Honda is bringing an upgraded engine to the Belgian Grand Prix, with Stoffel Vandoorne set to get a 35-place grid penalty because of the changes.
The Japanese manufacturer has been continuing to work on improving its Spec 3 power unit, which was originally tested as far back as the Azerbaijan Grand Prix.
But with the F1 season entering a power track double at Spa and Monza, Honda is using this opportunity to bring new parts it has developed for local driver Vandoorne.
Honda confirmed that changes were being planned, but drew short of stating what they were.
"Yes, we are bringing some updates here," a spokeswoman said. "[Yusuke] Hasegawa san will be available in Friday's conference to ask about the details of the updates.
"Regarding the penalties for this GP, this will be officially announced by the FIA on Friday."
The FIA has, however, already confirmed that Vandoorne will be taking an all-new powerunit. So it will be his fifth internal combustion engine, his eighth turbo, his eighth MGU-H, his fifth MGU-K, his sixth battery and his sixth control electronics.
That will be mean a 35-place grid drop.
It is understood that the new parts will only be trialled by Vandoorne this weekend but if they prove a success then Fernando Alonso could use them at Monza next weekend.