I just put an 8 3/4 rear into my shelby dakota last week. The 8 1/4 posi
unit was going bad, and I do a lot of drag racing, so I decided to use the 8
3/4 rear. My dad uses an 8 3/4 rear in his drag truck, and I know that has
in excess of 400 horses, and we haven't had any trouble yet. It's been in
there for about 7-8 years.
Also, I think I heard a couple of bad things about the 9 1/4 rear. Can't
remember what or who even I talked to
Later
Scott Miller
Shelby Dakota #322
94 V-6 Dakota Sport
> -----Original Message-----
> From: owner-dakota-truck@buffnet4.buffnet.net
> [mailto:owner-dakota-truck@buffnet4.buffnet.net]On Behalf Of Gary Shook
> Sent: Tuesday, September 21, 1999 7:12 PM
> To: dakota-truck@buffnet.net
> Subject: DML: Re: Rearend strength vs size question...
>
>
> >
> > Does the size of a rearend directly correspond to its
> > strength? I've noticed that it seems like the bigger it
> > gets, the stronger it gets, (i.e. 9 1/4 is an upgrade from
> > the 8 1/4 on the Dak, dump trucks have 12" rearends, etc.)
> > but is size the only determining factor?
> in general, yes... it has to do with leverage... the larger ring gear
> provides better leverage, and more surface area to push against
>
> >
> > The reason I'm wondering is, for a high horsepower
> > (drag racing) application, which would be better, the
> > tried and true 8 3/4", or the 9 1/4" from the R/Ts, Rams,
> > and late model Daks? Is the 9 1/4" stronger? I'm just
> > wondering because I see a lot of quick cars using the 8 3/4,
> > but I never hear of anyone using the 9 1/4. Is this a
> > price issue? A weight issue? A strenth issue? An
> > availablility issue?
> Probably price & availablity, as well as serviceability... the
> Chrysler 8.75
> rear is a quick-change design... pull the rear wheels & drums, turn a few
> bolts, slide each axle out 6-8", remove the driveshaft from the yoke, then
> remove the bolts holding the pumpkin on, and all the gears are
> out... if you
> have 2 pumpkins (one with street gears, one with ultra low drag gears) and
> you get good at it, you can change the rear pumpkins in about 20-30
> minutes... The 9.25 rear is very stout... I don't think a normally
> aspirated small block can break either rear end... the Dana 60 was used
> behind Hemi's and 4-speed 440s (Stick shifts are MUCH harder on
> rear ends..
> because of torque reversal and the proverbial "clutch drop")
>
> > Also, are rearends "rated" for a particular HP or torque?
> > If so, where can I find these ratings?
> Some guides I've seen rate rearends on what size tire you're running... if
> it doesn't hook up, it pretty hard to break one... I think 8.75's were
> recommended for 9-10" (wide) slicks, but don't hold me to that
> number (it's
> pretty fuzzy)
>
> >
> > Since I've torn the 8 1/4 out of my Dak once already, and
> > Eric has done so several times, obviously this thing isn't up to
> > serious drag strip duty. So, I definitely will be putting
> > in a stronger rearend in the future, but I'm undecided as
> > to what to use. Obviously, cost is a big factor, but I want
> > strength too. I'd like to get something that'll be able
> > to handle a thousand horsepower or so, rather than get
> > something intermediate just to have to upgrade again later.
> > Obviously I don't have anywhere near that much power now, but
> > who knows what the future holds?
> If you want the ultimate, you want the Dana 60 (9.75 ring gear if memory
> serves), it was known to hold together behind blown hemi's, but the 9.25
> should be more than adequate for a small block, even if it is blown.
>
>
>
>
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