I'm having a problem with the throttle return on my 1976 280z. I'm finishing reassembly after a complete restoration of the car and I've run into an issue with my throttle return. Most other Z cars I've seen have a large throttle return spring attached to the linkage on the throttle body and to a post bolted to a bottom screw attaching the throttle body to the intake. My linkage has no hole to attach the spring to and no post attached to the bottom of the throttle body for the spring?  Am I missing something?  The throttle does not return well at all. 

Took a couple pictures.  Looks like the bottom of the spring has its own bolted on little piece.  You can see half of the screw head holding it in the first picture.The top has a hole in the bellcrank, opposite where the plastic linkage ball snaps.on.  It's all buried behind the distributor and lower than the distributor.  

Hard to get to.  My car had a big spring attached to the valve cover and a piece of the throttle linkage, probably 'cause the PO couldn't get a replacement attached right..

They fixed it on the ZX and put the spring up top and easy to get to.

Since I have a couple of spare intakes to rob parts from, do you think the parts will interchange so I can switch them out?

Looks like they should.  I have a 78 system sitting on an engine in the garage but I must have removed the bracket, it's not attached.  But I did find it shown a parts diagram.  Part #28, I believe.  Looks like they only changed it once, in July 1975.  

http://www.carpartsmanual.com/datsun/Z-1969-1978/engine-280z/e-f-i/air-flow

14 hours - you've probably found it, fixed it, and moved on.