1st Start stock 340 w/ New or Rebuilt Carb?

Hello all,
Hope this is the correct forum for this question.
If not, please advise and I will repost.
Also, if there is already information on the, please point me in the right direction

Given that cam break in is so critical when initially starting the engine for the 1st time after a rebuild how can one assure the engine will start quickly on the first start assuming:

-Timing is set correctly
-New Carburetor or rebuilt Carburetor.(Don't know if adjusted correctly)

My concern being, using either of the above carburetors for the 1st time and not knowing if they've been setup or adjusted correctly.

I'd hate to be cranking endlessly because of an unknown/ improperly adjusted carburetor and possibly ruining a new cam.

Please advise and I hope this makes sense.