I was thinking of putting a 4 or 5 spd trans in my 1978 280z/auto. Is it more appropriate to leave the car original, I really don't mind the auto, or doe's it really matter if I disturb the original driveline? I have a 5 speed from a 79 280z, I also have 2 complete parts cars, a 75 and a 76 280z. What would be the best option and should I, if I do decide to do it use a different trans, your recommendations would be greatly appreciated. Also should the rear be changed?

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1978 DATSUN 280Z
1974 Lincoln Mark 16k orig
1949 Studebaker
1970 Buick GS 455 frameoff(sold)
inventory of Z parts 75-76

i found on gearbox changes on the 240 and 260 that there is very little you need to do...
The only change to the car you have to make is to cut the gearstick hole slightly bigger to allow you to get 1st gear..

-gearbox bolts straight in.. i think the rear mount is the same for auto and manual.

- speedo cable is same..

- clutch master cylinder should already have the hole in the firewall with a dummy plate.

- brake pedal comes out and im sure that u can put both brake and clutch pedal straight in without changing the pedal housing..

- tailshaft is same..

only problem i had was with the neutral start switch.. i couldnt figure out the wiring to get it to start. so i took the selector bit off the auto and kept it in the car with the wires still attached...
I think reverse lights can also be a prob>>

not much really though.. just wiring issues..
and if u ever want to put it back to Auto then you havnt totally changed or butchered the car to do so....

Make sure you use a later style box.. NOT A 240 BOX.
the gearstick should go straight into the box. not the one that has that stupid extention bit...

i changed a 240Z to a 260 box and the gearstick would hit the console..
no way am i gonna cut the console

Quite right, Pete ~ that's the "F4W71A" 4-spd box for the early 240Zed, and the "F4W71B" 4 spd or "FS5C71A" 5-spd boxes for the later 240s. The slushbox was called the "3N71B".

The early F4W71A box had that problematic "cup" holding the gear lever. (That happened to be the final thing that broke on my 240Z, which caused me to sell it in 1986:cry:).

The length btwn the U-joints on the automatic transmission propeller shaft is listed as 540mm (21.26"), compared to 520mm (20.47") on the 5-spd propeller shaft. ALSO, there is an apparent difference btwn the 5-spd propeller shaft and both the A/T and 4-spd shafts:

4spd or A/T: "Tubular shaft with two U-Joints and sliding sleeve at front end"
5spd: "Tubular shaft with two U-Joints and integral sliding section and flange mounting at front end".

The diagram isn't very clear, but appears to me that the A/T propeller shaft slides into the transmission tail section, while the 4 and 5spd shafts bolt up to a flange at the tail of the transmission.

The differential gears are different for each transmission, too. The A/T has a 3.545:1 ratio (240 or 260 ~ 280 was not yet made when my manual was printed). The 4spd 240 had a 3.90:1 ratio, and the 5spd had a 3.364:1 ratio.

What would be really useful is the overall length of each propeller shaft, and the overall length of each transmission, shaft, and pumpkin together. Of course the Haynes manual doesn't give that info.

Frank

So you guys don't think changing the originality is an issue. I find the auto to be rare but is it worth keeping?

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1978 DATSUN 280Z
1974 Lincoln Mark 16k orig
1949 Studebaker
1970 Buick GS 455 frameoff(sold)
inventory of Z parts 75-76

I would swap a 5 speed into it. Keeping it "original" means what? No one would know that the car was an auto and does not take away from the value putting in a 5 speed.

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Clive Bogle President - New York Z Car Club - NYZCC.COM
1971 240Z - LS1/T56
1974 260Z-L30
1976 Fairlady Z

Agree.
If you intend to show the car at hi-end auto shows, where there's big money involved and originality is important, keep the automatic transmission.

But if you want this car as a driver for your enjoyment and you prefer a standard gearbox, change it.

After all, it's YOUR car ~ and unless it's a very special, very unique or very limited classic, why keep it the way you don't want it? I can see leaving a very special car (like an early 240Z, for example) completely stock because there were so few of them and they're worth more unmolested. But HEY, if this is a Plain-Jane daily driver you want to have fun with, why shouldn't you?

You might want to keep the A/T in case the next owner wants to convert it back.

Great cars ars are meant to be driven and enjoyed. Think of what you would enjoy the most and pursue that path.

originalality......

take a good look at how original it is now.....
if you've got the original engine and all the compliance numbers match then your onto a good thing...
if you dont have the original block then you've nearly got no hope at all of finding it and making the car 100% original...

so if its already in good original condition then keep it that way...
if for whatever reason its not original and you have no hope in getting it back to original then go NUTS>>

My 260 2 seater didnt have the original engine so i've got no intention of keeping it original...

I appreciate the feedback. I have what it takes to convert it, I'm going to drive it a while, maybe a winter project while I paint it. Thanks again...see ya at the meets. Lou

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1978 DATSUN 280Z
1974 Lincoln Mark 16k orig
1949 Studebaker
1970 Buick GS 455 frameoff(sold)
inventory of Z parts 75-76

If you decide to swap, start searching for a pedal setup soon. You can't make a standard 'box work without a clutch pedal, and good setups for early cars are becoming hard to find. Those with hi miles have worn the pins inside the bushings so you get a LOT of pedal travel before the clutch actually begins to disengage, and engagement is sloppy.

Pulling one out of a parts car in the deep snow doesn't sound like much fun to me! The Club parts car ('71 Z) still has the pedal assembly in it, but I've already checked the pins and they're sloppy. They would have to be disassembled and have larger pins installed, or something, to make them snug.

The point is, if you think you might change it over the winter, start looking for a pedal set before the snow flies.

I have 2 parts cars, one is already stripped, the other a complete car running and all. Rot box though. Anyone looking for parts let me know. Thanks again frank

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1978 DATSUN 280Z
1974 Lincoln Mark 16k orig
1949 Studebaker
1970 Buick GS 455 frameoff(sold)
inventory of Z parts 75-76

I would just swap the whole drive train. If the 79 5-speed is all you have, that's fine. The 81-83 are the close ratio ones. (80 also, but has taller 5th) Also your 78 with auto has the R-180 rear, when you have 2 R-200 rears sittin in those parts cars. Keep the original stuff if you want to, but as far as value I wouldn't sweat it.

i would like to add my two cents to this question please. i have had 21 zcars and have found that a automatic is worth about half what a stick car is worth.at every show, and i attend alot of them, everyone comments that my car is an automatic, too bad. i don't think it's bad, but to someone else that hasn't driven one it's a curse. the car will be worth changing, just do it and be happy now and when you sell it. you don't ever have to say it was an automatic at one time, they will never know, and wouldn't care anyways. frank, i don't think the later cars had 390 rears for stick cars, check another book on those numbers. mike