Narrowed rearend options

[mklotz70]

This is just FYI

 

 

Was taking a couple of rearends apart. I believe the axle on the right is from a HBody. The one on the left is the typical H190 truck axle.

 

The splines are the same on both and the mounting flange at the backing plate is the same. The only difference between them is the length.......and the shaft thickness!

 

In the second pic, you'll see that the shaft is thicker on the HB axle. Meaning that they could be shortened and then re-splined to work in a narrowed H190 housing. The stock axle on the left cannot be shortened since the shaft becomes narrower as it gets closer to the backing plate.

[Guest DatsuNoob]

hmmm... I've heard that Subaru LSD rear ends are popular swaps for 510's. Just wondering if anyone has ever attempted a similar swap into a truck? It seems like my truck needs higher gearing to acheive better acceleration and top speed. Either a different tranny or rear end gears would be nice. I can tell that my engine has more power than what's getting to the ground, does anyone have any ideas for an upgrade?

[airedout]

If you need a rear end shortened, just send it off to Moser. They shorten the axle tubes, and make 100% new customs axles for right around $600. Easiest and safest way to do it IMO.

[mklotz70]

That's good info Dwight, but I think for $600, I'm going to be doing a better rear end than an H190 open diff! :)

[Redd]

cant go wrong with moser

[Bulletside]

yeah, how about a 6 bolt GM posi with disc brakes? I mean if your going to the trouble of narrowing something.

[datzenmike]

hmmm... I've heard that Subaru LSD rear ends are popular swaps for 510's. Just wondering if anyone has ever attempted a similar swap into a truck? It seems like my truck needs higher gearing to acheive better acceleration and top speed. Either a different tranny or rear end gears would be nice. I can tell that my engine has more power than what's getting to the ground, does anyone have any ideas for an upgrade?[/quote

 

Better accelleration and top speed are mutually exclusive. If you have a 4 spd, a5 spd with overdrive 5th is the perfect answer. you don't have to sacrifice accelleration and you have a high speed lower reving 5th gear.

I don't know what year your truck is, mine is a '78 and came with a 4.375. I replaced it with 4.11 and accelleration is terrible. I think the '79s came with 4.11s the rest were 4.375s although 4.88s were also available too. Some of the 720 trucks were down to 3.90 or 3.70? (I'm not at home and don't have my manual) The 720s had the Z series motors, specially the Z22 and the Z24's which had monster torque at low speed so these lower number gears were perfect.

[kiznook]

HBs have the h190, so is it a different size housing, but same diff? Why not narrow a h233b from a pathfinder, 233mm ring gear, optional lsd and disc

[OL YELLER]

OK dropped an 89 rear end in the '73..( I think it started as 4.735 and now is 3:70?) anyway, the acceleration is terrible but the highway (as in freeway driving is great)..70mph at 3000 rpm as opposed to the 4500 (or so) before)..good swap without doing the 4 to 5 speed switch..gonna do the trans swap in the '72 620 I am workin on now..see what the difference is that way......................................my 2 cents anyway

[mklotz70]

There's ton's of narrow rearend options out there. The only reason I pointed out these axles is because a DIY'er could use them and keep the cost way down. Narrowing the housing is the easy part if you have axles that can be resplined. Is it the best option? Absolutely NOT. Is this simply another option? YES. I'm not sure what resplining costs, but since I can narrow the rearend here, it might be an option in the future if I want to run rims with more dish on the NL. If I want to drive it in the rain....which in Portland means ...if I want to drive it at all.......I doubt I'll put a posi in the diff. A "one wheel wonder" is a lot safer when the roads are wet! Anyway....

[airedout]

There's ton's of narrow rearend options out there. The only reason I pointed out these axles is because a DIY'er could use them and keep the cost way down. Narrowing the housing is the easy part if you have axles that can be resplined. Is it the best option? Absolutely NOT. Is this simply another option? YES. I'm not sure what resplining costs, but since I can narrow the rearend here, it might be an option in the future if I want to run rims with more dish on the NL. If I want to drive it in the rain....which in Portland means ...if I want to drive it at all.......I doubt I'll put a posi in the diff. A "one wheel wonder" is a lot safer when the roads are wet! Anyway....

 

You need to get to work on the NL. I really want to see it much closer to the ground, with some nice rollers on it. I wish i could find one, but on the east coast thats damn near impossible.

[airedout]

although i cant say much, because i need to get to work on mine too.... :D

[mklotz70]

Since it's only going to be a static drop this year, it will be 3" lower and running on stock'ish' rims with rings and caps. I just got the 4th cap! :) I have brand new rubber for it....they have white walls...I need to see how it looks with the white wall out :)

 

oh....just ask the guys on the west coast.......it's damn hard to find one here too!!! :)

 

okay....enough forum...I gotta go pull that engine!

[mklotz70]

I do think the rims you have would look really nice on the NL....hint, hint :) j/k...I know you're putting them on something else.

[airedout]

I do think the rims you have would look really nice on the NL....hint, hint :) j/k...I know you're putting them on something else.

 

Actually at this point i may not use them on my next project. I'll let you know if things change.

[airedout]

There's ton's of narrow rearend options out there. The only reason I pointed out these axles is because a DIY'er could use them and keep the cost way down. Narrowing the housing is the easy part if you have axles that can be resplined. Is it the best option? Absolutely NOT. Is this simply another option? YES. I'm not sure what resplining costs, but since I can narrow the rearend here, it might be an option in the future if I want to run rims with more dish on the NL. If I want to drive it in the rain....which in Portland means ...if I want to drive it at all.......I doubt I'll put a posi in the diff. A "one wheel wonder" is a lot safer when the roads are wet! Anyway....

 

And damnit man, my way is the only way!!!!!!!!!!!!! :D

 

J/K of course, If i ever find a need to narrow my rear end, ill deff be looking into your option. Like you said, i dont know what it would cost to respline an axle, but i bet its less than $600.

[mklotz70]

Well...if I could narrow my rearend, I could fit into some of these fancy bucket sport seats!! :)

 

With a one wheel wonder you only have to replace one tire at a time! :)

 

Probably won't do anything with rims until next year.....we'll see.

[Guest DatsuNoob]

hey Mike,

I've got a 76 620, and am not too knowledgeable on the all the Datsun stuff(I've always had vw's), not really sure about which tranny I got aside from it being a 4 speed. Is there a way to improve both acceleration and top speed? What's the winning combination of tranny and rear end to have a nice compromise between acceleration and top speed? I'm looking for the best way to squeeze a little more go outta my truck. Thanks

[mklotz70]

:) I'm probably the wrong guy to ask about that. There's tons of guys on here that are into the performance end of things. My wife's 521 has a stock L16/weber/dogleg(same as 4spd gearing except for mild overdrive)/and 3.89 gears in the rear. I like the performance just fine and I've towed several other rigs with it. I wish my wgn had as much get up and go! :)

[datsunaholic]

Kinda the wrong thread for this, but to preserve existing Acceleration with a '76 truck, the only solution is to use a TRUCK or 280Z (not ZX) 5-speed and not change the rear end at all. A '77-78 will have the same 1st gear ratio as your existant 4-speed. The 5th will give a small overdrive, which at 60MPH equates about a 430 RPM difference.

 

A '79-80 truck 5-speed has a similar 1-4 but 5th isn't as tall, so you lose some of the overdrive.

 

A '81-83 ZX 5-speed has a much taller overdrive, but a lot closer 1-4 ratio so acceleration is badly affected (makes for great gas mileage though- I get near 35MPG with my '76 KC with an '82 5-speed, though acceleration is awful- 1st is so high it bogs down hard. It also only has an L18 which isn't much for torque).

 

It's all compromise. Changing the rear end is going to help one and hurt the other. Adding a 5th gear, irregardless of the model 5-speed, provides better cruising RPM (in 5th) than changing the rear gears, even to the lowest (3.88) you can get easily.

[dsigh]

I'm starting a new thread around Posi's so I don't hijack this one. I'm curious if a GM 6 lug is the way to go...

[fisch]

hmmm... I've heard that Subaru LSD rear ends are popular swaps for 510's. Just wondering if anyone has ever attempted a similar swap into a truck? It seems like my truck needs higher gearing to acheive better acceleration and top speed. Either a different tranny or rear end gears would be nice. I can tell that my engine has more power than what's getting to the ground, does anyone have any ideas for an upgrade?

 

I'd love an answer to this one too. Has anyone put a subaru LSD into a truck? Though I bet if it were a good option there'd be alot of them in trucks. Remember though I don't know squat.

[pope_face]

I think one of the issues with the Subi rear end is the fact that it's a 4-bolt (I think). That's why it works so well in the 510's. I'm pretty sure you could use it in a truck, and it might only require some modifications to the mounts, but you'd probably want to swap out the front for 4-bolt hubs as well... might be a good time for disc brakes...

 

Datsunoob: It probably is the wrong thread, like Datsunaholic said, but he makes a good point. The question you have to ask yourself is what's more important to you: accelaration, or top speed? These aren't just affected by your final drive ratio... the transmission ratios have a lot to do with it, as pointed out above. Not only that, but your wheel sizing can have a large impact as well... they're essentially an extension of your gearing. Also, your engine rpm's will play role in this as well... Assuming everything else is constant, a higher RPM will yield a higher top speed.

 

If you don't do a lot of highway driving, then sacrifice your top speed a bit and get better acceleration... it just means that when you do get on the highway, your revs will be a little higher. If you do a lot of highway driving, then figure out how fast you want to go and your preferred rpm's, and then select your gearing/tire size from there.

 

Don't get fooled into wanting stupidly high top speeds... you're unlikely to ever hit 200+ mph yourself, unless you've got a lot of money and a desire to end up in jail or dead, or have access to a speedway. For me, 160 km/h is plenty enough, and as long as I can hit 110 km/h at about 3/3500 rpm, I'll be happy. Sort out the highest speed you're likely to regularly drive, and then get your ratios from that.

[V8Dat]

The diffs that people refer to from Subaru to 510 are Independent Rear Suspension. Similar to the Z cars. The 510's and Subs used R160's , The early Z's used R180 and then the 280's used R200. Unless there is some way to take the diff apart and use them in the the truck housing I don't know. So it definitly would not be a direct swap. But a IRS rearend in a truck would be cool.

[Jester]

Like you said, i dont know what it would cost to respline an axle, but i bet its less than $600.

 

I priced having a Dana 60 axle shaft shortened and resplined at Dutchman tool in Portland. It was $55.00 per axle. They can also change the bolt pattern on your axle and drum/rotor.

 

Dutchman Tool: (503)253-6648

 

Jester