Via its Cadillac sub-brand, automotive conglomerate GM is already eyeing an F1 presence in the shorter term by partnering with the Andretti bid to form an 11th team.
Andretti has gained FIA approval to enter but is now awaiting a decision from FOM, which faces extreme resistance from the 10 incumbent teams who fear losing a chunk of their commercial income and any destabilising effect a new entry might have.
Andretti and General Motors chiefs are expected to attend this weekend's inaugural Las Vegas Grand Prix to lobby FOM for approval, with the new team targeting an arrival as early as 2025.
While that would require Andretti to agree an engine supply deal, most likely with Alpine, further down the line GM could build its own F1 power train having now formally registered as a supplier for the 2028 season.
GM president Mark Reuss said: "We are thrilled that our new Andretti Cadillac F1 entry will be powered by a GM power unit.
"With our deep engineering and racing expertise, we're confident we'll develop a successful power unit for the series, and position Andretti Cadillac as a true works team.
"We will run with the very best, at the highest levels, with passion and integrity that will help elevate the sport for race fans around the world."
GM has revealed that development and testing of "prototype technology" has already begun as it envisages using F1 to boost its understanding of electrification, hybridisation, sustainable fuels, high-efficiency internal combustion engines and software.
Should Andretti fail to get the green light from FOM, it is likely that GM will hold back on its F1 interest.
After Williams team boss James Vowles stressed how welcome GM would be on its own for the value it can offer the championship as a major road car manufacturer, Reuss reinforced that Cadillac's involvement was contingent on Andretti.
He said: "GM is committed to partnering with Andretti to race in F1. The collaboration between Andretti-Cadillac brings together two unique entities built for racing, both with long pedigrees of success in motorsport globally."