Here's why it didn't pan out.
If the Cadillac CT5-V Blackwing and smaller CT4-V Blackwing are to be the last combustion-engined muscle sedans from the luxury brand, then so be it. Like the rest of General Motors, Cadillac will become an all-electric brand with the Lyriq set to be its first EV. The Celestiq sedan will soon follow. It'll be the end of an era and the beginning of another one. Making sure Cadillac's likely last all-powerful ICE sedans were done right required serious commitment, such as the selection of the C7 Corvette Z06's LT4 V8 for the CT5-V Blackwing.
There was, however, another C7 engine briefly considered but ultimately deemed not doable.
Cadillac Society learned from V-Series Blackwing Chief Engineer Mirza Grebovic that the C7 ZR1's supercharged LT5 V8 was a candidate but there were issues.
"So if you put the LT5 in the CT5, we ran into simple issues - you can't see out of the car. In the ZR1, you can notice that it's a dry sump system and it uses that shaker hood. 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."
The CT5-V Blackwing, first and foremost, had to be a driver's car and the LT5, despite being more powerful (760 hp vs. 668 hp) would not have suitable for the CT5's chassis.
Grebovic further points out an LT5-powered sedan "probably wouldn't be any faster at the track or quarter mile, because 305 [rear] tires with that much power would be very tough to manage." Less is more, in this case. Building the best driver's car possible is so much more than just stuffing the most powerful engine possible under the hood. It's also about achieving an ideal power-to-weight ratio, a rightly tuned suspension, and, in this case, driver visibility.
The 2022 Cadillac CT5-V and CT4-V Blackwings are currently on sale with deliveries set to get underway at the end of this summer.