Best 5 speed to put behind an l16?

[73 smurf 620]

Been driving my 73 pretty far lately, an realizing that this 4 speed fawking sucks! Time for a 5speed, what tranny will bolt up to my l16?

[datzenmike]

Depends what you are hoping to get out of this. A 5 speed swap isn't going to be any faster as the 5th gear is really an overdrive unit that lowers the cruise RPMs to gain a slight mileage increase. You will will go just as fast or faster in 4th.

 

5 speed? FS5W71A, FS5W71B, FS5W63A, FS5R90A. There are also some competition boxes available from Nissan Competition.

 

I'll narrow it down to the two most common swaps, the FS5W63A and the FS5W71B.

 

FS5W63A

Unique in that the reverse is above first with an up over to the right and up into second giving it it's 'dogleg' nick name. L series doglegs have a 'close® ratio' gear set than the truck so take off with heavy loads will be more work... enpty will be no problem. It is the same length and has the speedometer drive on the same side as the 620 you have making it almost a 'drop in' swap requiring no driveshaft shortening. The rear mount will need to be modified to fit.

 

FS5W71B

Same shift pattern as the 620 but with an overdrive 5th gear. The 71B is almost 6" longer that the 73's 4 speed so the driveshaft will need to be shortened. The speedometer is further back and on the other side, but I have swapped a B into my 710 that has the same 4 speed, and by carefully running it diagonally across the top of the 5 speed it will reach just fine. The cost of modifying the driveshaft is more than made up for by having a much stronger transmission than the dogleg that was designed for use in a truck and the six cylinder Z cars. On top of this it comes in a variety of internal ratios and overdrive ratios. The rear mount will need to be modified to fit.

[ggzilla]

This question has been asked a million times. But since the Ratsun search box is broken, I can't say how to search.

 

The best 5-speed for an L16 is the 200SX 1977-1979.

[datzenmike]

This question has been asked a million times. But since the Ratsun search box is broken, I can't say how to search.

 

The best 5-speed for an L16 is the 200SX 1977-1979.

 

Search is broken??? how do you tell?

 

The easiest 5 speed for the '73 is the dogleg.

[ggzilla]

Search never finds anything useful if you use more than one word. For example if you search for best 5 speed, it returns stuff like 521 fuel gauge.

 

Easiest and best for an L16. 1977-1979 200SX 5-speed.

[73 smurf 620]

Ya im not expecting to get any more speed out of it, just a lower rom at 65-70 ish. It would be nice however.

[datsunaholic]

While the dogleg has the (lone) advantage or not requiring driveshaft mods, a thing to take into account is that you don't NEED to have the driveline shortened to use the longtail 71-series transmission. All you need is the front driveshaft from any 74+ 620, since they all used the longer transmission and hence have the correct front driveshaft for a swap into a '73. You would also use the crossmember and rubber mount from that as well, and the speedometer cable.

[OL YELLER]

Ya im not expecting to get any more speed out of it, just a lower rom at 65-70 ish. It would be nice however.

 

Now then, here is another way to lower your RPMs on the highway...replace the stock rear end with one from

a later hardbody....we(my son and i) had the swap done by Cal Mini Trucks here in the Inland Empire bout

8 years ago....changed to the 3:70s out of an '89....cruisin now at 70 mph and the tach reads just at 3k..(not the almost

5k stock)...ez swap...and relatively inexpensive.........same stock 4 speed, same speedo cable, etc...

[superbee620]

would a 5 speed out of a 1984 720 work in a 1973 620 L16 ?

[Draker]

Not without changing the front case out.

[wayno]

It's not the only transmission that doesn't require a driveline mod(dogleg), but it is the easiest one to convert to, but you can use a shortshaft 5 speed out of a 1985/86 Nissan regular cab/short box 2wd truck, and the front case off a 1980 Datsun 720 4 or 5 speed, this transmission will fit anywhere a dogleg will fit, but it is way stronger, although I will admit it is not easy to find the required parts.

Doglegs are getting harder to find all the time, one day then will become an endangered species, right now I would call them threatened.

While the dogleg has the (lone) advantage or not requiring driveshaft mods, a thing to take into account is that you don't NEED to have the driveline shortened to use the longtail 71-series transmission. All you need is the front driveshaft from any 74+ 620, since they all used the longer transmission and hence have the correct front driveshaft for a swap into a '73. You would also use the crossmember and rubber mount from that as well, and the speedometer cable.

[datzenmike]

would a 5 speed out of a 1984 720 work in a 1973 620 L16 ?

 

Not easily. First it will have to be a 2wd transmission or you will have no speedometer. Second, the '85 will need an earlier L series 4 or 5 speed front case and front cover swapped on to convert it for your L series 1600 engine. You will also need to remove the 62mm counter bearing and buy a 56mm counter bearing for it. (this is not a hard job although it sounds like it). Third, is the '85... 26" or 31.5" long. If 26" long it's ready to install. If longer the drive shaft will need shortening OR, you can find  a later '74 and up 620 and get the shorter front driveshaft off of it and put in yours. Probably cheaper.

[abbylind]

Larger diameter tires and rims helps too...lower rpms

[superbee620]

I wanted to chime in and ask about 5 speed swap. ive got a 73 620 with a 4 speed. just bought a 5 speed out of a 83 280zx I can see that the 5 speed  is about 4 to 5in longer than my 4 speed tranny. I also have a 78 or 79 620 junk truck tranny is 4 speed but same length as the 280zx 5 speed and the front drive shaft is about 4 to 5in shorter than the drive shaft behind the short tranny in the 73 . this drive shaft should just bolt up with the 5 speed shouldn't it ?. thanks

[datzenmike]

yes.

 

Try the '78/'79 transmission crossmember and rubber mount also. I don't think the earlier 63 series 4 and later 71B 4 use the same ones.

 

The '83 zx has an awfully high over drive (25.5%)  for a L16 powered 'heavy' 620.  I'd be curious how well this drives down the road at 60 into any wind.

[superbee620]

Thanks datzenmike . you are always right on point. I appreciate the advice. ill let you know how it does in 5th

[datzenmike]

To be clear it will work just fine. In comparison, the mid ratio might be a little more comfortable in a truck. If some day you swap an L20B in, it would be much closer to perfect.

[superbee620]

thanks again datzenmike. its all coming together now.

[ggzilla]

The best 5-speed for gear ratio availability is the Nissan FS5R90A. Came in 1982-1983 Datsun 280ZX Turbo, so fits L-series engines. Gearsets are available reasonably priced in just about any ratio, for example ultra-close ratio can be paired with steep rear gears to keep the high-revving L16 in the power but with a very high 5th for quiet and economic highway cruising. Or get a wide ratio for less shifting and easy driving. Whatever you want. Its the good mustang type T5, not the despised GM T5.

 

Of course there are easier swaps (63A), and more common 5-speeds (71 series).