I'm Batman

I was discussing these in another thread, but it started to seem like a hijack, so here we are.

They appear to be based off of something noted (but not pictured very well) on page 6-4 of the Chevy Power Manual, 5th edition. They totally eliminate the rubber bushings - the stepped portions fit snugly into the crossmember bores. I'm fairly sure that they're steel, but I'm not 100% certain. All dimensions are approximate.

Upper ring dimensions:
total thickness - 9/16"
thickness of wide section - 7/16"
thickness of narrow section - 1/8"
diameter of wide section - 4"
diameter of narrow section - 3 13/16"
diameter of hole - 2 9/16" (it appears to taper a bit as it goes downward - it's around 2 1/2" - 2 17/32")

Lower plate dimensions:
total thickness - 7/8"
thickness of wide section - 7/16"
thickness of narrow section- 7/16"
diameter of wide section - 4 1/4"
diameter of narrow section - 3 13/16"
diameter of hole - 1/2"

I have no idea where they came from, I got them with a used crossmember and spring assembly. The original blue finish looked like a factory job, but it also looked quite old and worn.

SHAKERATTLEROLL

So what is the ? . And you are correct about the Chevy Power Manual but you would weld them to the cross member. And I feel it would be worth while to make enough notes to be able to duplicate them.

But the ones you show look as though you could put them in without welding. The power manual shows how to make them but they are welded in. It looks like you have something special.

As I for one would be very interested.

rpoL98

I had gotten a set of those a while back (more than 10 yrs ago), made of solid aluminum, with anodized blue finish. I don't see them being sold any more, only the bottom aluminum disk part which goes on the bottom of the factory rubber bushing to help hold the diff crossmember more solidly. I might've gotten them from Guldstrand perhaps, but they don't sell the spacer that goes between the crossmember and the frame anymore.

Separately, to get completely away from the rubber bushing a la Chevy Power Manual, I had some steel spacers machined up at the local machine shop. I took the factory rubber bushing out of the crossmember, and separated the steel center "cup" part from the rubber and steel outer shell. then I welded the center "cup" portion to the steel spacers, and welded this assembly to the crossmember, top and bottom. It worked out pretty good, using the aluminum biscuit for the front diff mount.

This mounts the diff solidly to the chassis. there wasn't a lot of gear noise transmitted while driving. I've done this for two C3 diff crossmembers.

I'm Batman

These were originally blue, then had a layer of black spray paint on top of that. They may be aluminum, but they feel rather heavy for AL.

-------------------------------

I started this new thread to stop hijacking another one with the discussion. Other than the source, I don't have any questions about them. However, several posters were curious about the dimensions, and I figure that if anyone wants to have a set made up they might find it useful.

ZD75blue

That is really cool.

Wonder where the rest of us could find something like that?

(Might even get weight reduction from it... those rubber hunks are heavy!)

I'm Batman

I'm sure a good machine shop could turn some very easily. They're pretty simple.

1970-Bronze

So, if it is "better" then why isn't the suspension suppliers selling them....?

I'm just trying to understand.

redvetracr

Dick Guldstrand has been selling them for years....I have a set of used discs if you or anyone else is interested.....$25 delivered anywhere in the lower 48 states.
...redvetracr

68 NJConv 454

There must have been a reason GM went thru the trouble of making the diff xmember removable with rubber inserts. I'm sure it would have been easier and cheaper to just weld or bolt them together. I would think the rubber would not trasmit any vibrations thru to the chasis from the diff. RPLO98 says he didn't feel much vibration but there has to be a reason, maybe the small constant vibrations would losen chasis bolts?? just throwing out ideas.

Pretty cool though.

If I auto-x'd i'd buy a pair.

I'm Batman

Auto manufacturers seem to be obsessed with sticking rubber everywhere. I never really have understood why.

68 NJConv 454

We've had it implanted in our brains... always use rubber
no rubber...no good

ZD75blue

My .02 is gear harmonics from the differential...

If you've ever driven a car that has the lash set wrong, the rear axle wants to jump out of the car.

Would be less than pleasing on the vetter, where you practically sit on top of it...

I'm Batman

The reinforcement discs should have the same problem, then, and I've never heard of anyone complaining. If they're annoying, oh well...I'll think of something else.

emersong

I am interested if you still have a pair of those Guldstrand rear crossmember locating disks. Emersong@me.com

emersong

I would love to buy one or a set. One of mine fell off and is on the hwy somewhere. Please contact me emersong@me.com