If you fix (and probably rebush) your SU carbs right they will be sweet.

All the serious problems I have had with SU carbs (at least HS and HIF models)
I can attribute to them being so badly worn that they were untunable (and you
can fix this with new throttle shafts and rebushing the body) or that I didn't
know what I was doing in tuning them. Mostly the former. For some reason
there is a big mystique about SU carbs but I think it has mostly to do with
their advanced age and related wear plus massive failure to understand their
simple principle of operation. And many of the manuals are not as clear as
they could be, either. But they are really pretty straightforward, and when
in good condition are widely adjustable and can be made to be very tractable
while still giving good performance, a LOT better than a downdraft carb.
--
George Downs Bartlesville, Heart of the USA!