On another thread, we were discussing the resale value of a Tesla needing a new battery pack, and somebody was talking about replacing everything with a conventional V8 and drivetrain.
I think you could have a pretty good unit if you took a cheap used hybrid, AWD version, needing a battery pack and replacing it with the minimum of cells or cells and mega caps...then bumping up the HP via a turbo or transplant...keeping all the electric drivetrain and controllers.
About 300HP ought to do it.
Probably both a mechanic and an electrician would need to collaborate on building this project.
Your project seems quite fun but challenging. Most hybrid transmissions don’t have a torque converter, and use the space to package the motor/starter windings. AWD also needs space for a transfer case and additional driveshaft. A conventional powerpack would need to have a place for the starter, which is always located outside the radius of the torque converter. This space is likely used up by other items, including locations for the driveshafts and half shafts. That’s quite a challenge.
The exhaust system has to go through all that space, too, and a turbo needs additional plumbing. After all that, the wiring might be quite easy since there would be less of it and it is not rigid. The good news is that the space where the battery pack was might give extra cargo capacity...if you can get to it.