With a 6.2-liter supercharged V-8 engine that produces 668 horsepower and 659 pound-feet of torque, the Cadillac CT5-V Blackwing is the most powerful and most track-capable Cadillac model the automaker has ever made. The LT4 engine deserves a lion’s share of the credit for that, but if Cadillac really wanted to raise the CT5-V Blackwing’s output figures to full-fledged supercar heights, the 6.2-liter supercharged LT5 engine could have been offered in the CT5-V Blackwing. Caddy ultimately decided against using the LT5 engine, in part because of the myriad of issues that would’ve cut into the appeal of the CT5-V Blackwing.

Fit was the biggest issue Cadillac had with using the LT5 engine on the CT5-V Blackwing. Cadillac V-Series Chief Engineer Mirza Grebovic told Cadillac Society that the LT5 engine could’ve been used on the CT5-V Blackwing, but it would’ve at the expense of major changes to the makeup of the sedan.

A shaker hood, for example, would have been required on the performance sedan if it was powered by an LT5 engine. "We couldn’t put a shaker hood on the CT5,” Grebovic said. “You would have to make it so high that you can’t see outside the car, and we wouldn’t have met regulatory requirements for vision.”

Driver visibility issues aside, Cadillac would've also been required to use dry-sump lubrication on the CT5-V Blackwing, something Grebovic indicated wasn’t necessary on the CT5-V given the different architecture between the Cadillac and the C7-generation Chevrolet Corvette ZR1, which was powered by the LT5 V-8 engine.

On the contrary, it would’ve made the sedan more difficult to drive because, as Grebovic points out, the 305 rear tires that the CT5-V Blackwing comes with would’ve been “very tough to manage” with that much power under the hood of the sedan.

All things considered, the LT4 engine was the right engine choice for the CT5-V Blackwing.