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Whats a stronger (than stock) rearend , for a 1970 BB ??

  • Thread starter Thread starter SwaveDave
  • Start date Start date
Oh, I feel better now....

That Ford IRS is a standard "porsche-style" inboard brake model...

http://www.dutchmanms.com/1_indep9rears.html

That was the only one I saw on the 'site.

These are the bolt on frame section things common in streetrodders, but these are apparently a nightmare to install in a vette as they are "thicker" front to rear than the vette, don't use transverse leafs and, most importantly, don't use the vette-type trailing arms at all, which isn't clearly shown in the diagram. These use a three longitudinal arrangement rather than the vette lateral and minor longitudinal. This of course entirely changes the mode of wheel aspect retention and alignment and again, is completely different and experimental in achieving balancing.

This design was precisely what I asked about from the custom rod place in west Texas, only made by Heidt's. As I said before, they literally begged me not to do it, telling me there would be little left that was "vette" after finishing.

The inboard brakes are a monster to get cool air to on a vette. Not only that, but installation requires a re-arching of the frame rails, changing the rear fender wells and more or less complete elimination of the interior cargo wells.

...not a "drop in" replacement at all! Sooner or later someone could and might make an altered 9" center section only for the vette system....but this isn't it. I noticed they offer some nifty halfshafts that might be available in vette format....hmmm....but then again lots of vendors offer those directly in vette format.

The whole set-up WAS $4K, without gears, but all polished and powder coated, which is really a hell of a lot cheaper than the TD center section only near $3K, with no suspension parts included.

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On the Eaton site I could only find applications for light SUV's, although regular Eaton differentials were listed for vettes. From what I could gather the main carbon fiber components were the posi-trac bits and MAYBE the case....the gears they mentioned being some sort of forging.... I don't know what to make of it. I would think you could get away with even more being carbon fiber, but I only saw one picture of the assembly and it had no labelling to say what part was made out of what. They seem to want you to ask them directly after filling out a huge e-mail return form.
 
Re: Oh, I feel better now....

WayneLBurnham said:
That Ford IRS is a standard "porsche-style" inboard brake model... http://www.dutchmanms.com/1_indep9rears.html
Yup ... that's the 9" IRS I was thinking of. Inboard brakes like an old E-type Jaguar ... I recall jag rears were also popular w/ streetrodders. I did a bit of price comparison on their related stuff ... they're almost double-$ on base 9" 3'rd member and on base quickchange ... see other vendors' ads in Circle Track magazine for better pricing on such items. 9" is toughest thing out there ... but not bulletproof. We've bent two (crash) & burned up two others (setup?, bad lube?) ... just this season. Hmmm ... maybe the next time we toss a 9" housing because of a bent tube ... I'll save it for another winter project ... maybe.
JACK:gap
 
How DARE you say that stuff is HIGH!?!? :)

Jack said:
I did a bit of price comparison on their related stuff ... they're almost double-$ on base 9" 3'rd member and on base quickchange ...

But it's BILLET Dude!!! :Silly CHROME!!! :_rock KNURLY!!! You can't put a mere DOLLAR value on that!!! ;LOL

9" is toughest thing out there ... but not bulletproof.


Yeah, that's very true. Any part can break and will. A decent Ford 9" setup, highly modified with all the best 'go-fast' parts, perfectly balanced, can tolerate maybe 1500 ft-lbs on a long term basis and maybe 500-750 more on short term, but it's not an industrial truck "mover." 'Real' 4-Wheelers (unlike 'ess-yu-veeers' :puke ) learn this quickly when they try to use what's known to be strong on street machines with 40" 75+ pound lugged wheels pounding into rocks and other huge shocks. Only problems with those industrial size things is the huge rotating mass is slow to spin up, tolerates high RPM poorly and weighs so much it eats performance. The Ford 9" design is just one of the best made in that weight and use class - and that quick-change deal is just beautiful.

You know, if you have a spare 9" sitting around and a regular vette one it may look reasonably straight forward.

Of course you'd need to make inner axle rigs with seals and flanges and such and the QC may be a little less "QC" - requiring pulling the half shafts and then inner axle to change the gear set. The half shafts themselves may need to be shortened, but that's not a bad idea. Of course the up front mating would be different, but driveshaft alterations are old hat and not a problem with a design that hardly moves the thing vertically anyhow.

If, instead of cutting and altering and generally butchering the diffy itself but rather make adapters and change the mounting geometry to the frame and spring the whole project may require less critical and almost experimental internal machining. In other words use the stock external geometry of the 9" and adapt what it bolts to rather than attempting to alter it to fit where a Dana 44 fit, things look less monumental.

All that may be "only" on the order of adapting a C5 transaxle to a C3 (or rather actually adapting a C3 to use a C5 transaxle), which has been done. If the emphasis is changed to adapting C3 suspension and driveline to utilize a 9", the whole thing looks a little less scary and "high tech".

I think if somebody successfully made a "kit" to put any 9" Ford on a C3 vette that kit would prove more popular than other higher-priced alterations for many modified C3'ers. Who cares if that kit included some big aluminum adapter and mounting plates (which would also be a very useful heat sink/cooler for the cooling-deficient IRS differential) and an altered spring and halfshafts in the kit? (...and required altering the driveshaft...)

Being the kind of idiot who spent $4500 installed for a part rated for an engine I won't build for at least 2 years, I know I'd be a customer! There must be other equal idiots in the modified old vette community! :Twist
 
I think Wayne is onto something...

I don't have much experience with this, but I think that taking removing the halfshafts from the suspension (ie, using some form of multi-link suspension to change things so the halfshafts are no longer responsible for horizontally locating the spindles) is already a good idea. And often requires adapters to mount the links. So, a combination kit that would modify the suspension to a multi-link setup, and adapt the mounting positions for a new diff seems like a natural combination. Plus, eliminating the differential as a load-bearing member of the suspension seems like it would make converting to a different differential much less difficult...

Anything can be done, with enough $$$

Joe
 

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