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transmission swaps


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Wow man,you didn't even get the do a search reply.Ok in a 73 with a 4-speed swap to the zx 5-speed is plug and play,question is why do you want the 5-speed? fifth gear is an overdrive,are you looking for fuel economy or are you into the numbers game,more being better.

I know what you are going to say 5 speed is better,but look at it this way,do you really want the output turning faster than the input? all it's going to do is put your engine behind the power band.Especially if you got stock rear gears.

I had to replace my original 71 4-speed about 10 years ago and I thought about the 5-speed but at the time I needed to get it done fast and could not find a good 5-speed.So I got a 4-speed from a 78 280z,I rebuilt it,put it in and have not had a problem since.

Pretty sure your 4-speed is the same one I got,unless it's giving you trouble I would leave it alone. As for resale,most people prefer the 5-speed so I don't think anyone would mind if it was in there already,you would just be saving them the trouble of doing it themselves.It might even help resale.

Well that's my opinion and like A** holes everyone's got one.

Edited by Zforce
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Charlie, welcome to the group. Forth gear in a 5 speed is direct drive the same as 4th in the 4 speed. As what was stated the 5th is overdrive.

That being said, if you have a L-24 engine , over drive will be below your power band unless you lower the differential gear ratio. If your Z now has a 4 speed then you have 3.36 to 1 ratio. If it is a automatic then 3.54s, in 5th the engine will lack torque due to the low RPM. 3.70 or 3.90s would be a better ratio. If you would like to get more lower end performance and are now running a manual tranny. Install a 3.54 differential. This will lower the ratio and you will notice more off the line , but you will lower the top end slightly. This is a straight across install if you stay with a R-180 diff.

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Another benifit of the zx 5 speed is the ratio spread as well as the trans being stronger. I love mine but I did not care about resale but that does not matter unless you are building a trailer queen. I have run diff ratios from 3.54 to 4.44; 4.11 is my favorite with the zx 5 speed running 205/60/14's (tire diameter changes things). I have a bigger cam in my motor so the power band is higher than a stock motor but I still prefer the 5th gear for higher speed cruising. I can always downshift if I need too. The inside of the car is quiter in 5th than 4th which is why I like it for the highway.

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