actually- the volume of my setup is considerably more.
The initial expansion makes a huge difference in power
as for oil to fuel - my 32-1 setups make most power -for me
My 50's (ZDZ) like large systems and tuned systems .
good systems run 7500-7700 rpm on 22x8 Mejzlic
the DA will do about the same.
Most in cowl mufflers KILL power
The header in the pic of the DA is way to close on initial bend at exhaust flange but the other sharp bends really don't do much harm For decent flow the first bend should not be nearly so sharp see pic attached