[RLHMARINES]

The LT5 was ruled out mainly due to the fact that it wouldn't fit its wet sump height since a dry sump was not needed for this particular car fitted with the maximum sized rear 305 tires only along with the taller blower and its 760 hp from what was said at the BlackWing presser from a Cadillac rep.

https://cadillacsociety.com/2021/03/...lt5-v8-engine/

In an interview with Cadillac Society Executive Editor Alex Luft, V-Series Blackwing Chief Engineer Mirza Grebovic provided some insight into the choice to use the LT4 rather than the LT5.

“When we initially started working on this project, obviously we were super excited to shove any engine in there and make as much power as possible,” Grebovic said. “But in the end what we have to balance is a driver’s cars.”

As it turns out, outfitting the Cadillac CT5-V Blackwing with the LT5 would result in a number of drivability issues, starting with visibility.

“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 LT5 found in the Corvette ZR1 is also notable for its dry sump lubrication, which simply isn’t necessary in the CT5-V Blackwing. As Grebovic points out, the CT5-V Blackwing runs different tires than the ZR1, and thus won’t generate the sort of cornering forces that necessitate a dry-sump setup.

“Not doing a dry sump didn’t allow us to drop the engine as low, because the architecture is very different,” Grebovic adds.

Additionally, more power wouldn’t necessarily make the car any faster, given the modifications required to put the extra muscle to the ground.

“So yes, we considered the LT5, but aside of just engineering issues, let’s say this car did make 760 horsepower. We wouldn’t have the right chassis for it,” Grebovic said. “It would have been a powerful car, but it probably wouldn’t be any faster at the track or the quarter mile, because 305 [rear] tires with that much power would be very tough to manage.”