You are correct about the 240Z style R180, but - if I understand you correctly - your description of the 260Z style R200 is wrong (no offence). This is the way it works:
- 260Z R200 uses short, splined 'stub' axles which literally snap into the diff centre using a circlip arrangement (in fact this arrangment has carried through to S15, R32, Z32, etc). There is no bolt holding them in. Where the half-shafts attach to the stub axle there are 4 studs with nuts and lock washers.
- 240Z R180 uses similar stub axles BUT has a single long retaining bolt for each stub axle (ie up the middle of each stub axle). Again at the half-shaft end there are 4 studs + nuts, etc for attching the half shaft.
In fact the half-shaft stud pattern is the same between 240Z and 260Z which is why it's possible to bolt an R200 into a 240Z without changig the halfshafts (and similarly for R180 into 260Z) although there are other things needed, of course.
There are other arrangements for half-shaft attachment in other cars that use R180. For example:
- 240K/C210 Skylines use a single bolt to attach each halfshaft, but in those cars there's no 4-bolt flange to attach the halfshaft to the diff. Instead, the uni joint mount (or half of it at least) is integral to the halfshaft - effectively the stub axle and halfshaft + uni's are an 'assembly'.
- Cars that use CV's for the halfshaft (eg R30 Skyline) use a clip in arrangment for the stub axle (like 260Z), which, again is integral with the shaft itself.
Hope that helps
