Here is a post from another site from a guy I know that worked as a Z specialist for Nissan for about 25 years. He knows his stuff, and this was the longest post I'd seen from him yet on ANY subject. You can trust this to be absolutely correct stuff....
"just to clear up a couple of tranny points.......
all 77 to 83 non-turbo 5 speed trannys will bolt directly into a 240z
only the first two year 240z needs to have the shift opening enlarged to accept the 5 speed. from 72 on ,it is a simple bolt in operation.
if youre 240 is a 70 or 71 you will also need to space down the rear tranny mount to help correct the driveshaft angle.
the reason the shift hole is different on the early 240z is due to the fact that the tranny shift lingage was an external tower type that came up higher and needed a smaller hole.the later 4 and 5 speed tranys have all internal shift linkage and a much lower tower and the hole was enlarged for shifter clearance whether a 4 or 5 speed tranny is being used.
the earlier tranny is a great trans but is better suited for a 240 if you do not plan on swapping out the diff assy for improved gearing.the later zx tranny is linked with a 3.9 diff and has both good low and high end . if you put an 82 83 5 speed tranny into a 240 with original diff gearing it is a bit sluggish off the line.
one last note of interest.....
all trannys in z cars have brass synchro rings. the later zx trannys all have brass synchros as well. the gears are steel and the synchro rings are brass, even in the turbo trannys.
so if youre thinking of using the later zx trans because it has steel synchros and will last longer be advised. there are no steel synchro rings in the trannys that we have discussed.
as far as improvements from old to new 5 speeds the biggest difference is that fact that the old 5 speeds mainshaft nut used to loosen up with time and needed to be replaced . in the later zx trannys they reversed the thread pitch on the mainshaft and nut, therefore , the mainshaft nut no longer worked its way loose as time and mileage went on."
Hope this helps some people out......
Carl
"just to clear up a couple of tranny points.......
all 77 to 83 non-turbo 5 speed trannys will bolt directly into a 240z
only the first two year 240z needs to have the shift opening enlarged to accept the 5 speed. from 72 on ,it is a simple bolt in operation.
if youre 240 is a 70 or 71 you will also need to space down the rear tranny mount to help correct the driveshaft angle.
the reason the shift hole is different on the early 240z is due to the fact that the tranny shift lingage was an external tower type that came up higher and needed a smaller hole.the later 4 and 5 speed tranys have all internal shift linkage and a much lower tower and the hole was enlarged for shifter clearance whether a 4 or 5 speed tranny is being used.
the earlier tranny is a great trans but is better suited for a 240 if you do not plan on swapping out the diff assy for improved gearing.the later zx tranny is linked with a 3.9 diff and has both good low and high end . if you put an 82 83 5 speed tranny into a 240 with original diff gearing it is a bit sluggish off the line.
one last note of interest.....
all trannys in z cars have brass synchro rings. the later zx trannys all have brass synchros as well. the gears are steel and the synchro rings are brass, even in the turbo trannys.
so if youre thinking of using the later zx trans because it has steel synchros and will last longer be advised. there are no steel synchro rings in the trannys that we have discussed.
as far as improvements from old to new 5 speeds the biggest difference is that fact that the old 5 speeds mainshaft nut used to loosen up with time and needed to be replaced . in the later zx trannys they reversed the thread pitch on the mainshaft and nut, therefore , the mainshaft nut no longer worked its way loose as time and mileage went on."
Hope this helps some people out......
Carl
