rear dif gearing

[paul leary]

Have '67 Datsun 520 p.u. with an engine conversion, Buick 231 V6, turbo 350 trans, orig. rear dif with stock gearing 4.875, looking for other gearing to drive fwy speeds. What options do I have .....?

[datzenmike]

Have '67 Datsun 520 p.u. with an engine conversion, Buick 231 V6, turbo 350 trans, orig. rear dif with stock gearing 4.875, looking for other gearing to drive fwy speeds. What options do I have .....?

 

 

Depending on year an model the H-190 was abvailable in... 3.364 to 4.625 (at least)

[Farmer Joe]

go to the junkyard and look for the 3rd member (center chunk) from a 720

 

under the hood on the passenger side inside fender-well will be the tag explaining all the options that truck had.

 

itll show you the engine number, the trans ID and the reared ID...

 

the tag will look like this...

 

 

this truck had a z24, 5 speed and 3.54 gearing... the HE35 you see is the decoded for the rearend... 35= 3.54, 38= 3.889, 41= 4.10... etc...

 

have fun man! try and find the 3.54s if you can... with that big motor, the lower the batter. you have to torque to move em.

 

edit::: dammit mike... you beat me to it... lol

[datzenmike]

:fu::lol:

 

The 3.364 was also on the Mileage option 720 with a Z20(S) engine.

[Farmer Joe]

:fu::lol:

 

The 3.364 was also on the Mileage option 720 with a Z20(S) engine.

 

 

yeah i remember that... ive havent come across a 3.36 chunk yet... fairly rare now..

 

the pic above was one of the 2 trucks ive seen with a 3.54...

 

i want the 3.54 with a KA! roadtrip anyone? lol

[monk]

are the rears for the 521 and the 720 the same?

 

 

[Farmer Joe]

yes sir!

 

both have the H190 rear end... third members are interchangeable..

 

this is why i love datsuns....

[paul leary]

Have '67 Datsun 520 p.u. with an engine conversion, Buick 231 V6, turbo 350 trans, orig. rear dif with stock gearing 4.875, looking for other gearing to drive fwy speeds. What options do I have .....?

4.875 final drive in my manual, I'll have to open it up to really tell. thanx for the info.

[ggzilla]

Fit the GM 4-speed automatic ... then you'll have more power AND better fuel economy than stock. And can keep your existing gears.

[Farmer Joe]

even if he had a 2004r overdrive trans, with 488s is still gonna be revved out.

 

they even had a .67 overdrive.

 

the th350 is the second best trans for parasitic power loss.. the gm overdrive trannies are not too efficient with the lower HP version of the buick v6..

 

IIRC all the old GM cars with the RWD buick v6s, excluding the grand national, had either th200c lockup style 3 speed, or the th350.

[ggzilla]

"not too efficient" is better than not efficent at all, as the three 3-speeds at highway speeds.

[datzenmike]

4.88 is too low for such a big motor, and not just the economy, the potential for traction loss, while lots of fun, can wear thin for day to day driving where you have to watch the weather and road surface conditions. The most common rear gear is the 4.375 found mostly in the 620 and super easy to swap out. Most 720 2wd (avoid 4x4s) were in the 3.90 range and Maxima goons did run around 3.50 or so.

[DRIVEN]

I've always found this useful when selecting transmission and rearend gearing:

http://www.angelfire.com/fl/procrastination/rear.html

[Z-train]

200r4 with 3.54 would be about PERFECT.