I've gone all those routes (Webers, cams, electronic ignition, hi performance carbs, balh blah. in the last 25 yrs of driving a B. Nothing does much good for the thing.
I'm doing a GM V6 conversion. It's fairly cheap and gives a modern. reliable drivetrain. It does not require any mod to a rubber bumper car. I bought a shabby but lo mileage firebird v6 with std trans and a conversion kit. It went together easily, and the total cost was about $2000.