I am sure the Buick had a "crossover" pipe linking the two banks of exhaust together and thus all the exhaust is powering the turbo.
I figured
Hank,when speaking of the 6.5 turbo --" no carbon seal. Made to run fuel & air through the compressor wheel."
Dont you mean ... NOT... made to run fuel and air through the compressor wheel?
Yes, thank you for correcting me, brain fart.
If the turbo does not have a carbon seal in it, you cannot run fuel & air through it.
Good catch! 