Jerry - the venturii are the same; but the throttle body on the 2075s is larger than on the 871s; thus the transition into the intake manifold is smoother. Also, the metering calibrations are different, to allow for the better airflow of the larger throttle body. Again proving that, while venturi size is a major component in air flow, it is not the only component.
I didn't check all of the vents, restrictors, bleeds, etc.; but if I were still doing carbs, I think I could do the conversion in the machine shop in 14~16 hours. Machine throttle body, fabricate new throttle shaft, fabricate new throttle valve, resize main jet, power jet, and (I didn't check) maybe both idle tubes.
Just increasing the jet sizes without the throttle body change would probably do little, maybe nothing.
Jon.
