Setting carbs for first time

[MGMagnette@aol.com]

I rebuilt the engine myself, and had the carbs done by Joe Curto.  New  vac 
advance too.  Timed the engine with the starter spinning to something  close to 
spec.  But since the carbs are rebuilt, they are so far off I  can't get the 
car to start.  It will run very briefly, like for a second or  two, backfire, 
and stall.  I honestly don't know where to even begin.   Advice?
 
-John