There were big differences between my '91 GMC Jimmy and a '91 Chevrolet Blazer.
Rims for instance.. wait.. no.. those were the same.
Doors were different.. wait.. no.. those were the same too.
Glass had to be different right? Nope. The glass out of an '87 Blazer fit right in my '91 Jimmy.
Ok, so my Jimmy had a crappy digital dash that was notorious for not lasting more than 10 years.. thats a difference, right??
With the parts so interchangable, it makes me wonder why the heck GM even makes a "GMC Truck" and a "Chevrolet Truck" but I guess it boils down to marketing.
The Camero and the Firebird were pretty much the same car, just different headlights and tail lights.. the Buick Regal, Olds Cutlass, Chevrolet Monte Carlo and Pontiac Grand Prix were all the same car, too.
Chevy Chevette and Pontiac T1000.. same car.
I just happen to like the way the Chevrolets look better than GMC, as a general rule.. altho I think I like the new GMC grills better than the new Chevy ones.