Reason to replace 240z transmission to Z31 5-speed?

[Mailorder]

From what I understand, it's popular to replace the 240z's 4-speed transmission with the Z31's 5-speed transmission. But is there a reason to replace it if there's nothing wrong with the current 4-speed? Are there significant performance increases? The truth is that I'm about to purchase a 240z for $2000 and while I'm interested in performance, for now my focus is just to use it as a daily driver.

[evildky]

close, the whole idea of swapping to a 5 speed si to get overdrive, the 4th gear yields a 1:1 ratio, when cruising at interstate speeds this means your engine will be spinning pretty fast, if you get a 5 speed you gain overdrive and your engine will spin slower at interspate speeds de to the increased gear ratio

and the Z31 isn't the trans tou use, some 77-78's came with 5 speeds, these are a bolt in, the 79-83 280ZX n/a's came with 5 speeds also I a bolt in, the 81-83 280ZX Turbo used a t-5 which si a lot stronger and better for race applications but requires a custom driveshaft and trans mount to go in

you can use the n/a z31 trans but it requires you to use the frotn case and coutershaft bearing fomr a 72-78 trans and requires a custom driveshaft and custom trans mount

another benefit to swapping to the later 79-83 280zx style transmissions is a tighter shifter, the 70-71 uses a terrible saddle type connection that yields the loosest sloppiest shift you'll ever find, the 72-78 isn't terrible but the 79-83 is much better and the t-5 is the tightest of all but also the heaviest

[Mailorder]

Very in-depth, thank you!

[evildky]

I've run about every possible trans in my 240Z, I'm not proud