My old four speed is making some very strange noises and I think its time to build up my L-28 and mate it to a ZX 5 speed and swap out all of it at one time. I know I have to use 280 clutch components, but something in the back of my mind says I also have to change out a structural piece. I know about the mod to the transmission tunnel but what am I forgetting? :paranoid:

Disc, P/P, Flywheel, and Throw-out bearing arm & collar, & slave cylinder is all I am aware of that would need changing.

when you say ZX I assume you mean 79-83 280ZX? in which case all the clutch components swap over just fine, all 70-83 N/A cars used a 225mm flywheel/clutch, all Turbo and 2+2 models used a 240mm flywheel/clutch, the turbo used a T5 tranny which will require you to modify your trans crossmember and have a custom driveshaft made casue the 280ZXT used a unique output spline, the throwout collar was made a bit longer at some point I am thinking 72 was the first of the longer throwout collars and they stayed the same size through 83

There are at least 3 sizes of T.O. bearing collars out there.

Throw-Out bearing collar information can be found at THIS WEBSITE

i found out the hard way it took 3 goes before I got it right and I hate lifting a transmission on my back under the car that's for sure

Carl is correct about the throw-out bearing collar! Just use the collar assy that is standard issue on the ZX trans. I believe the earlier collars for the 4 speed are shorter and won't work properly.

Does the trans crossmember modification only apply to the 70/71 models or all years 240?

for the T-5 all 70-78's require trans crossmember mod, the T-5 mount was further back ( I am thinking on the 71.5-78 it's not as far out), I am not sure about the N/A 5 speed