240z SU carb rebuild kit question
 

Hey everyone,
I recently purchased the 240z round top SU rebuild kit from Zcardepot.com and was curious which needles to use M39 or M43. Every where I read a N prefixed needle is referenced. Also, what are the washers replacing? Thanks in advance, here is the link.https://zcardepot.com/fuel/carbureto...z-1970-73.html

The needle to use depends upon how you want to tune the carburetors. The taper of the needle affects how rich/lean you are running. SU Carb (very) Fine Tuning ? Moss Motoring
As for the washers, they replace...existing washers. SU Carburettor, SU Carbie Perth, SU Performance, SU Australia - Holley Performance Parts

As you are rebuilding the carburetors, look for play around the throttle shaft. That indicates wear that will let in extra air.

Thanks for the info, I appreciate it. Turns out, after an email to ZTherapy they should be for a 4 cylinder, 38mm carb. So the kit goes back.