I was able to take my 75 280z out for a test run with the 81 ZX 5speed today. Wow is all I can say, what a difference. I have the 3.54 diff and find it a very nice match up with the tall 5th (.75). I was concerned that the taller 1st may be a problem but it was a non issue, can barely tell the difference when starting off. From there its only better. The gears seem better suited in all traffic conditions, and when I was on the open road I put into 5th and was going 75mph at about 2600 rpm, 80 was about 3000. Prior to this 80 was 4000 (60 was 3000, 70 @3500). The car seemed much quieter and perfectly happy with the load (credit the torque of the L-28). Needless to say I am thrilled with this modification, I generally like to keep things completely stock, but this is just so much better I feel its worth it.