I'm working on a complete restoration on a 73 240Z.  When I bought the car, I also got a 72 engine and manual trans with it. My intentions were to use the round tops off the 72 and install them on the 73. I'm nearing that part of the project, so I started looking over the carbs on the 72.  I do not see any choke plates.  There is linkage where the choke cable would connect, but no choke plates or shafts.  Are the chokes a separate attachment to the carb housing that I don't have?  I know the ones on the 73 are incorporated in the carb bodies.  I tried looking at the fish diagram for the 72 but can see anything that helps. any enlightenment would be greatly appreciated.

z3beemer

Are you looking for a separate choke from the throttle plate in a round top SU?

There is no separate choke plate in a round top SU. The nozzles in a round top drop when the choke lever is pulled and the throttle plates open a little more. This richens the mixture up.

Good to know.  I didn't see any typical choke plates and didn't know if something was missing or that was the way it was supposed to be.  The linkage is there but didn't see anything moving when I operated the linkage.  Knowing there's not supposed to be choke plates is a big relief.  Thanks