TR4 carb tuning

["James A. TenCate" <jtc@ccwf.cc.utexas.edu>]

A naive question:  I'm supposed to help a friend tune up the carbs on
his TR4(A?).  I've done it a bunch of times on TR6's and 7's but never
on a 4.  Are the TR4 carbs SU's or Zenith/Strombergs?  Will the same tool
that adjusts the needle on the ZS carbs also work on SU's?  When did
British manufacturers switch over to ZS (or was it just a North
America smog thing?)

Yes, yes, these are pretty basic questions but I figure you guys should
know.

Thanks,
jim