If it could get past the British who feared the idea of creating an entity they couldn’t control and the colonies that didn't want to give up their autonomy to a centralized government (maybe by the French posing a greater threat in North America and more British troops are needed in Europe?) then I think you would get a loose confederation that mainly serves as a way for dealing with Native Americans as was the original purpose of the Albany Congress. This could cause some butterflies in the Pontiac War and while the Proclamation Line would probably still exist since the Americans adopted similar methods used by the British after the war but it would be far more favorable to Americans as they’re the ones dealing with the Natives. It could also butterfly away some of the Intolerable Acts that caused the American War for Independence so later on when things like taxes, representation, and paying for the damages of the seven years war become issues this Union could centralize into a real government and maybe avoid the Revolution with America as a self governing nation but still a part of the British Empire.
I don't know if Quebec would matter in this, or if it would mean better relations with Native Americans, or if America would be bigger or smaller in size. But this would butterfly away Wild West and that slaves in the South would be growing indigo instead of cotton.