I want my cake and eat it too, thought more along the lines of cut 2 audi heads and weld them together as a 6 .
Combustion chambers are way too big and will need filled.
Pump will have to move down to clear the intake, but a front timing belt is plenty long. New injector pipes.
they may not be designed for diesel stress, but it's a good motor, and can hold a lot of power.
here is one with 1150 HP.
https://www.youtube.com/watch?v=TRpbvpmVfJE