If you're talkin about P/N: 38-1260, the Uni Syn, they SUCK!! At least I think so.
I used to have an engine in my car that ran dual Weber 40 IDF carbs. Basicly one individualy tunable barrel per cylender, and that particular item about made me want to blow up my car,...
Of course what Drew said is the 1st step, assuming you havea tight system and a set of matched carbs, the Uni-Syn can work, ok-ish.
STE synchronizers are better by vast amounts, and of course like many tools, you pay a bit more for "better".
They are very easy to use and dont require and fiddling around with adjustments on the tool at all. Take it out of your tool box, pop it on the carb, and take your reading.
I bought one long ago and still use it today, this thing is the poo for setting up multiple carbs. I highly recommend them.
