Differences Between the Buick Enclave and GMC Acadia Photo: Buick While Buick and GMC are both upmarket GM brands, their midsize SUV offerings have their share of differences. Here’s a look at the differences between the 2021 models of the GMC Acadia and Buick Enclave Photo: GMC The Enclave only offers one powertrain option: a 3.6-liter V6 engine that churns out 310 horsepower and 266 lb-ft of torque. When equipped with front-wheel drive, it earns an EPA-estimated 20 mpg in the city and 30 mpg on the highway. All-wheel-drive models fare similarly — they return 20 mpg in the city and 29 mpg on the highway. The Acadia comes standard with a 2.5-liter four-cylinder engine that offers 193 horsepower and 188 lb-ft of torque. In terms of fuel economy, it offers 21 mpg in the city and 27 mpg when cruising down the highway.