Jerry---I don't think you'll be able to comply with the emissions setup
with the SU HS6 carbs. It is said that this is the reason for going to
the ZS, which is further developed along those lines. That doesn't mean
you can't tune the SU to run at the ideal Air/Fuel ratio, when the SU is
in good condition. You can. What is missing are ways for all of the
emission hoses that are on the ZS carbs to connect to, plus the bypass
(engine overrun) valve, a port to provide ignition retard vacuum, and
such. (You might find a port for vacuum advance, but only the early
distributors had a pot to use this.)
What the SU is more versatile in, is the needle choices. One has to know
what is needed for their particular application, and/or a method to
check the A/F ratio. Otherwise, there's really no advantage over the ZS,
in my opinion, and I have used both types.
Dick T.
|