I am looking for an engine for 2017 Verano. The mechanic has an engine that he says will suit my car (it might be from equinox or terrain). The flywheel had teeth on it if I recall..I don't see a flywheel with teeth on my car but I think it has a belt on the flywheel. Is the engine interchangeable. If so, equinox is bigger car, is there any concern over gear ratios or additional wear as it is a heavier vehicle ?

Thanks.

My information says that the LEA was installed in the following:

2012–2013 Regal
2015–2017 Regal
2012–2017 Verano, Captiva, Equinox, Terrain

Many areas in the nation have restrictions on the production year of the engine. Usually this requires that the engine is the same model year or newer than the model year of the vehicle it is being installed in. If this is the case in your area, you'll want an engine out of a 2017 model year donor.

All flywheels have teeth. They are flex plates really, but still they have teeth. No belts.

Should be. The core parts are the same. All of the stuff that bolts on around it is more specialized per vehicle platform, but even then a lot of it will cross over.

Yes the different models are slightly bigger and smaller than one another. It isn't significant enough that I'd worry about it. Besides, you could get one from another Verano that was beaten its whole life or from an Equinox that was treated nicely its whole life. There'* no way to know that. What I would look for is to get a donor engine from a car that had been totaled in a rear-end collision, or maybe a side collision if it didn't affect the engine bay very much.

Regarding gear ratios, that is in the transmission. As far as I know, you should be replacing the engine only.