Hello recently purchased and old 1979 rx7 racer that was a barn find. I am rebuilding the carb and I'm pretty sure that this spring/rod assembly is supposed to be mirrored in the other float chamber. Can someone confirm this and if so know where I could get a replacement

 

Funny enough that's actually exactly how it's supposed to be - that rod is only on one side. FB carbs ditched that system entirely. If I recall correctly, it's essentially a vacuum controlled plunger and there's a needle valve threaded into the bottom of the rear float bowl that it contacts. Then again I haven't messed with an SA carb for a while, although it's something very close to that in concept.

And by the way, welcome to the club! Nikki carbs are a fun setup on these engines and have a fair bit of potential if you ever feel like modifying them. I'll be curious to see what happens with your project. Best of luck!