primary throttle shaft

[Michael9040]

How do I determine if my base plate needs to be sent to you for bushings?  There is some play, of course.  I could set a dial indicator on it if you could suggest a max play.  Also, the basic bowl is drilled the same for all  metering rods, correct.?  In other words, I could take a 350 carb and and rejet it for 427 use.

[omaha]

in my opinion, do the bushings. Even if they are slightly worn {id say anything over 3 or 4 thousanths for sure}
This would be like a preventative measure as the new bushings have lubrication properties built into them.  The engine wil idle alot more stable and consistent witht the new bushings compared to one that has play at the shafts. If you decide to do the bushing later, it is not much of a problem to remove the base plate only from the carb without taking the whole carb apart.
    #2 question; yes, all carbs can be reconfigured to go from smaller engine to a larger one.
You can use either of the two size castings {basically}. the secondary jet orifices are all  the same size.
Primary jets are easily changes also. [but it is more involved] it can be a flexible carb on some things and some things you gotta pull it off the motor. Get the primary sid e dialed in and you can play around with the secondary rods without tking the carb off the motor. My 2 cents FWIW.

[Cliff Ruggles]

Most throttle shafts are going to show some side play.  It's a good idea to install bushings to prevent a vacuum leak at the primary shaft.

The secondary throttle shaft requires some side play so the huge throttle plates can relocated and seat in the bore each time they close.  It is not recomended to install bushings for the secondary throttle shaft.....Cliff