Always best to know YOUR location, cuz many people do not want to ship these, cuz they are so big bulky heavy!

Teddyeddy 1

Posted May 1, 2023

You should be able to find something there!

The picture is of a '79 zx 5 speed and is a mid ratio used only that one year on the 280zx. If you really want the close ratio with the big 25.5% overdrive 5th, have the seller put it in first gear and turn the input shaft 20 turns while someone counts the output turns. A REAL '80-'83 non turbo close ratio zx 5 speed output will turn 6.5 times

A mid ratio 6 turns. Most common ratio and used on cars and some trucks.

A wide ratio 6.5 turns. Used mostly on trucks.

Know what to look for and get what you pay for.

Teddyeddy 1

Posted May 2, 2023

If you are not particular about the exact trans gear ratio, just locate ANY 1977-1983 280Z/280ZX 5speed!  The three possible ratio's are actually all pretty close...............it's usually a pretty serious car guy looking specifically for the "close ratio" 5speed.  You will also pay more for the "close ratio" if the seller knows what it is!  You mentioned you are "still learning".  Yes the "close ratio" is a little better, but I bet you wouldn't notice with one of the other two!

There is a later 1981-newer NAPZ 5speed that came in the 720 truck & the 1981-newer cars that can be used, but you MUST swap to the earlier 1972-1979 4speed bellhousing or the 1977-1983 5speed bellhousing.  If you find something & not sure, take a clear pic from the rear of the trans to the front, at a slight angle from the top.  One of us should be able to tell you what you have!  There are NO NUMBERS or markings to identify...........it's all visual ques!! 😆

Also, as a self proclaimed "still learning" (newbie!!), just an FYI you can NOT tell if a trans is good by only shifting it!!  I hear it all the time............."this trans shifts fine (sitting on the ground)!".  Means NOTHING!!  You either DRIVE the car it is coming out of before pulling it out, get proof it was rebuilt with an invoice OR you should assume that these 40++ year old transmissions are worn or damaged.  I also hear "It worked fine before I pulled it!", which you either trust the seller or not!  Rebuild kits are available online, but rebuilding is not for the faint of heart...........they are kinda complicated, LOTS of little parts inside!  You can always toss a USED trans in & cross yer fingers, if you don't mind the labor, but too often the bearings & synchro's are worn out, thus requires a rebuild!

Teddyeddy 1

Posted May 3, 2023

The only down side to the '80-'83 non turbo close ratio is the over drive. It's really tall, like 25.5% and used is cars with six cylinder 175 hp that can use it. You do have a light 510 so that is a plus as the engine has less work to do.

Most L series mid ratio are half that at 13-14% and will get more use at lower speeds. 

At 50 MPH with a 3.9 axle and stock tire the 510 is revving about 3K. If you had a later close ratio 5 speed and put in 5th the RPMs drop to 2,200. At 2,200 the engine may not be making enough power to cruise at highway speeds and certainly going up grades and into a windy day there may be challenges. At 60 MPG it's 3,400 in 4th vs. 2,550 in 5th. That's a big drop.

Teddyeddy 1

Posted May 3, 2023

This should clear things up on the close ratio 5 speed  compared to the wide ratio 

https://www.classiczcars.com/forums/topic/64504-fs5w71b-transmission-identification-close-ratio-vs-wide-ratio-with-pictures/