I have a 1975 280z with a four speed. When I bought it, the guy had a 5 speed as well that he gave me. It is an earlier wide ratio 5, but I'd still like to drop it in there to see if it's good. My brother, the pro mechanic, may pull it apart, just to see if the inside looks ok before we put it in. So, aside from the internals, is there other things I need to worry about? i.e.:

- Do the 4 and 5 speeds use the same clutch and throw out?

- same driveshaft and flange?

- same tranny mount hardware?

- I seem to have read a thread that suggests the shifter is a little long. Is that long on the top end, where I just cut an inch off the top, or is more finesse required? Is this a real incompatibility, or just a preference for a short throw shifter?

- Anything else I forgot?

I drive the car pretty regularly (it's my daily driver, when I'm not on my motorcycle), so I'd rather not get everything apart to find out I need part X, that is back order for 4 weeks.

thanks the the info.

Geof

As long as you keep the parts from your 4 speed (fork, throwout bearing collar, pressure plate)together as a unit, you should be fine. The B type 4 speed shifter (from my '73) was actually 3/8" longer from pivot point to the bottom than the later shifter I had come across. This provided a slightly shorter throw. Even so, I still had about 1 1/8" taken off the top of the shifter.

I spent about $120 in parts to rebuild my 5 speed before I put it in. New bearings, baulk rings, and seals. All gears were in good shape.

It is a straight transmission for transmission swap for a 280Z. Except for the 4th gear vacuum advance switch if your car is a 1975 Federal, not a California, model. The five speed probably does not have it, so you will need to hook up vacuum advance full-time or rig up a switch.

Use all of the parts that you have in there now, except the transmission. Shifter, throwout bearing, everything. The only difference you will notice is the 5th gear. 1st through 4th gear ratios are even the same, if by "earlier" you meant 75-79.

I did the same swap in my 1976. 5th gear is nice to have on the freeway, even at 55 mph. Very nice at 70.

Edit - tlorber beat me to the punch while I was typing. I think that in your case, your 280 4 speed shifter is the same as the 5 speed shifter. Both transmissions came from 280s and are externally almost identical.

Edited June 6, 201113 yr by Zed Head

Cool. Thanks for the info. I was guessing it would be ok, but wanted to make sure. Mine is a 1975 california, and is mostly intact. What is the federal vacum advance thing? It advances timing in higher gears?

Geof

I believe it actually retards timing in the highest gear. I can't remember if '75 are Atkins motors or not. If not, you could always bypass any emissions garbage.

The switch enables the vacuum advance in 4th gear to give the engine a little extra torque. Assuming that the VA actually works in your distributor. When they get old they often fail.

As for the transmission swap, the throw-out bearing and collar have to match the clutch, not the transmission. Do a search on the subject. There are several old threads that go into great detail.