A couple s-10's

Thanks Worx,

I don't know if I could get the geometry right without moving the motor wayyy back. I've only played around with the idea in my head. I know others have done it but just fit it in anyway they could and called it a day. I don't think there is anyway to mount it up front of the cross member and be able to clear a sway bar. Honestly I've just thought about it and that's as far as I've gotten.

Cleaned up the diff yesterday,






My dad works with delrin a lot at work. So we thought about making up some busings for the 2 mounting points. The current ones are rubber that is cracking and getting quite hard/malformed. I'm questioning if delrin would be to rigid.

Also I'm trying to find a posi carrier for this 7.2 front diff. There is really only 2 choices, stock/open and a locker. Which is not really an option. There has to be an import with something close that could be retro-fitted into the case.  

I have an Auburn pro series in mine, but I have the 75/8 front diff, which i was going to recommend you get if you're going to invest any money into a front diff. you can put the awd yoke on as well.

I have a stock 75/8 front diff that i bought as a spare a while ago when someone had told me i had to modify my front diff to go AWD, but i didn't. I just needed the pinion yoke from an AWD. I had a drive shaft made.

What spline/ size input shaft do you have for you t case? Do you have the giant one, and the giant output shaft? I don't want to take mine apart to check specs, but i bought a t case built for 4l80 and big nuts from a syty guy up here.

Do you have any info on the 7 5/8" front diff? I'm curious what vehicles it came in. I didn't see an auburn posi unit listed for one. Can you link me to it?    I was thinking about trying to retro-fit one of the amc Dana 30 TRUE - TRAC's.

Dana 30
 Ring Gear DIAMETER 7.20"
10 3/8" X 20 RH THREADED BOLTS
PINION DIAMETER 1.376" 26 SPLINE

American Axle 7.25
Ring Gear Diameter 7.25"
10 3/8" RH Threaded Bolts
PINION Diameter 1.315", 27 Spline

It will fit but I'll be doing different case bearings and seals. I'm just unsure of the alignment. I think I'll have to make custom bearing races as well.

It's all up in the air right now. It's free to read and throw ideas around and that's about all I can afford at this moment lol.

As for the tcase off the top of my head I'm not sure to be honest. It's a bnib stock astro van case. I want to say 27 spline but as for the size I'm honestly not sure. If you really need the info let me know and I'll dig it out of storage and take some measurements for you.


nothing really to update, just did a major garage clean out over the weekend. It still looks like I did nothing though...

I believe it is the same diff stock non rear disc/ non zr2 and 2wd s10's have. Or is that the 7.5? i cant remember. As for your t case/ center diff, its not that important, so you don't have to go thru any trouble. I've seen two different awd cases, one had a pretty small dia output shaft and one had the biggest dia output shaft you could get from a GM. I have always planned on a V8 swap, so i went for the big one. The cases themselves, both looked the same to me, but this was a few years ago and i can't remember any details.

I smoked my 4L60 and changed to a 4L80, and i bought the center diff all at the same time. The only thing i've needed for years has been some HP. The rest of my rig is ready for it.

I really like that mustang in your driveway. Is it yours? what year, 68?

i find it really weird that your Dad has no motivation to work on it..

I believe it is the same diff stock non rear disc/ non zr2 and 2wd s10's have. Or is that the 7.5? i cant remember. As for your t case/ center diff, its not that important, so you don't have to go thru any trouble. I've seen two different awd cases, one had a pretty small dia output shaft and one had the biggest dia output shaft you could get from a GM. I have always planned on a V8 swap, so i went for the big one. The cases themselves, both looked the same to me, but this was a few years ago and i can't remember any details.

I smoked my 4L60 and changed to a 4L80, and i bought the center diff all at the same time. The only thing i've needed for years has been some HP. The rest of my rig is ready for it.

Yes my understanding is there was 2 different tc's made. The biggest difference being the spline count was slightly higher on the later model. Honestly I really don't know though.

Just so I'm understanding what you are saying you are running a gm 7-5/8" solid front axle? not an ifs?  The 7-1/2" or 7-5/8" are the same thing, from what I understand. Aside from a slightly larger ring gear and I believe 26 or 27 spline everything else is the same.

It's my dads '70 302. Zach I don't know what's up with it really. I mean it's in beautiful shape. It has a couple of minor flaws and my dad is just a mad perfectionist. I told him just put it together and enjoy it if you don't have the time/money to get everything to be absolute perfect. Maybe next year. 

I have a ZR2, so it has a larger front diff, and I believe it is the stock 2wd rear diff size. I'm still independent up front. I believe that ZR2 drivelines are perfect for a Sy/Ty clone build.

My old man is the same way. I can appreciate the perfectionist, but sometimes i start to lose my patience with him being too anal.

From what I've learned, the ZR2's and 2nd gen manual 4x4s had a cast iron dif casing, but it retains the same sized internals as the other 4x4s.  Should be the 7.5/7.625 like you're saying.

^ Yes Zr2's came with a different case cast iron vs aluminum.
They are the exact same center section though;

American Axle 7.25
Ring Gear Diameter 7.25"
10 3/8" RH Threaded Bolts
PINION Diameter 1.315", 27 Spline

Your rear axle in a Zr2 would be a 12 bolt/8.5 ring gear.

For a second there I thought there was some mystery front diff out there that would have dropped right in lol. Man that would have been nice, thanks for trying to help though SCHLAKER.

Your rear axle in a Zr2 would be a 12 bolt/8.5 ring gear.

8.5s are still 10 bolts

Yes sorry that's right.

Hey No Problem man.

Back to the original question about differentials or lockers, I lived in Salt Lake City when I bought my front and rear Auburn Pro series. I bought them througha place out there that does buggies and prerunner stuff. it was about 6 yrs ago now, and I'm still having a brain fart as to what the shop was, or the PN for the Auburn Diff.

Since Eaton and Dana have a big presence in the Twin Cities, I have been thinking about going right to the manufacturer for part numbers and fitment for our trucks.

On the subject of Axles, I just bought a 9" for the Monte with a Nodular 3rd member in it, and 2 other 3rd members for $600. The coolest thing about it is the guy had already been running it in his circle track car and it has really nice 4 link mounts for G body cars. I got 4.56, 4.11, and 3.08 gears already in the 3rd members.

Sorry if I sound braggy, but I'm really excited about it now.

I would be too, congrats!

Wow. This is an incredible build thread. Subscribes.

^ thanks,

Hey No Problem man.

Back to the original question about differentials or lockers, I lived in Salt Lake City when I bought my front and rear Auburn Pro series. I bought them througha place out there that does buggies and prerunner stuff. it was about 6 yrs ago now, and I'm still having a brain fart as to what the shop was, or the PN for the Auburn Diff.

Since Eaton and Dana have a big presence in the Twin Cities, I have been thinking about going right to the manufacturer for part numbers and fitment for our trucks.

On the subject of Axles, I just bought a 9" for the Monte with a Nodular 3rd member in it, and 2 other 3rd members for $600. The coolest thing about it is the guy had already been running it in his circle track car and it has really nice 4 link mounts for G body cars. I got 4.56, 4.11, and 3.08 gears already in the 3rd members.

Sorry if I sound braggy, but I'm really excited about it now.

I would love to hear what eaton and or dana would have to say about parts for our trucks, particularly the front differential. Nice buy on the 9" and goodies.

I've just about got my whole front suspension put together now. Coils can wait until I have a better idea of the corner weights. Sway bar will have to wait until I figure out if I'm going to mess around with the steering linkage.

I'll be using Sport Machines lowers,



and these SPC adjustable uppers,



For the spindles I've choosen c5/6's that have been massaged by SC&C,



Over the winter we'll be making up some billet steering arms as the ones that came in the kit way back when were not intended for a half-shaft,


Penske 8760 triple adjustable adjustable fronts and 8300 double adjustable rears,



some weight comparisons,






11 lbs









I should have weighed a stock shock but these have got to be a good bit lighter. It would be interesting to compare torsion bar + shock to one of these coils over shocks + coil.




This was a product put out by SC&C several years ago marketed as the G5 suspension package. It's one of the best if not the best suspension package ever developed for a G-body imo. It's to bad they made so few and stopped making them because of cost. If these spindles ever break I'm in a real conundrum.

Notice the ball joint orientation, stock 4wd is a reverse,



it's about the equivalent of a 4wd drop spindle, I haven't done a side by side comparison for an actual measurement of total drop,



from a previous post,

My current American Racing Torq Thrust M's 17x8's weigh 50lbs each.

The front 18x10.5's weigh in at 45lbs each.
The rear  18x12.5's weigh in at 49lbs each.

That's 12lbs in rotational and un-sprung weight savings with more grip,


I've been planning on keeping a tally of the weight deductions as I went along to see what I've really gained in the end,

Stock Uppers - 8lb
SPC Uppers - 5lb


Stock Lowers - 23 lb
SM Lowers - 9 lb

Stock Spindle - 11 lb
C6 spindle - 4 lb

Total Stock weight - 42 lb
Total Modified weight - 18 lb

I was really surprised by the difference in the lower control arms at 7lbs a piece without the balljoint. Kudos to Tom at Sport Machines that's over 1/3 less. I wish everything was that easy when it came to dropping weight.

With 3 components I've shed 24 lbs of weight from both sides of the truck. After the wheels that comes up to 29 lbs per side. Nearly 60 lbs shaved off the front and some great parts to replace it.

 I'll have to find one of the stock shocks and weigh it to compare to the penske. The stock unit is pretty beefy if my memory is serving me correctly.

My goal is to completely offset the weight added by the awd components and maybe even come out better. So far I'm at 116lbs. After calipers/rotors, sway bar, potentially r&p steering I'm hoping to get close to 150lbs.

Those are some really gorgeous parts, congrats. I don't want to know how much you have into it all though.

Wow - this is going to be a sick build 

My stock 2wd shocks were 3 lbs as were the double adjustable QA1's.  I was hoping for a difference too, but everything else did well.


IMG00121-20110811-1918.jpg by TheHarley, on Flickr