Sure-Grip Options for a mildly built 440

[FastbackJon]

My Charger didn't start out with a 440, so one of the things I still need to add is a sure grip to the back.

I'm not all that keen on what needs to go in though, whether it be a locker, or a sure grip unit or what, or what the best choices are.

Right now in this '66 Charger I have a mildly built 440, HP cam, headers, .040 over, and out back is a 489 case 8.75 with an open diff.

So Randy's has a list of lockers/sure grip units...

http://www.ringpinion.com/PartsList.aspx?SearchMode=Diff&TypeID=2&Type=Chrysler&DiffID=8&DiffName=Chrysler+8.75+(89%2c41%2c42)&CatID=9&CatName=Positractions&CatType=Sub-Differential

I guess my questions are:

1) Do I probably have 30 or 33 or ?? spline axles?
2) Which unit will install the easiest in my standard open carrier case, the locker, or the sure grip unit, or are they the same thing?
3) Which unit is better for what I will use it for? I enjoy the occasional burnout, I don't drag race at the strip. I'm thinking I don't need the most expensive one, and that the cheap one might get me by, unless it is not as reputable or will not work as good.
4) Is Randy's a good source for the parts or is there a better alternative, in terms of cost (incl shipping) and customer serivce?

Thanks

[Runner]

call doctor diff,  hes somwhat local to us (polson montana), a great guy and knows rearends.  im pretty sure you wont beat his prices and im absolutly positive you wont beat his customer service.  during the sale and after(the most important part of customer service in my opinion.)   


    id think you should have 30 spline axles.

[WM23N1G1]

I still haven't finalized my deal with Dr Diff (my fault), but he is a very knowledgeable guy, very patient, and willing to listen to potential buyers.

[Ghoste]

The lockers are different from the usual limited slips and use a kind of ratcheting mechanism instead of a clutching plate affair.  Oversymplifying there a bit but the short end of it is that you'll likely be happier with the more common style.  I have a lot of Ford friends and even quite a few of them aren't crazy about the locker on the street.  Their complaints are small, it's noisy and "jerky" going around corners.  Of course, other people swear by them but I still think for the occasional burnout, go with the common limited slip. 

[firefighter3931]

  The clutch style suregrip is what you want.


Ron

[Finn]

So this: http://store.summitracing.com/partdetail.asp?autofilter=1&part=DCC%2D4876118&N=700+400172+304615+4294902583+4294925083+4294908110+4294908099+115&autoview=sku is or isnt clutch style?
I see cone type but I dont know what that means.
Im trying to put a...well now that Ive seen all the options Im not sure so Ill just list what Im looking for here:

Something that hooks up to a 440/727 with a 8.75 rear w/3.23 gears
Will light up BOTH tires
Still allow daily drivability with good corning manners.
Im guessing that a limited slip would fit all these?

Im debated swaping the gearing out now or later as well. A guy I talked to recommended 3.55s but my question is will I notice the difference? Someone linked me to a nifty site that had an rpm/gearing/speed thing that showed the rpm differences.

Also is there some type of system (like air/cable lockers) that could be engaged/disenaged as desired and would it be worth it or more of a hassle than its worth?
thank guys

[Ghoste]

That one isn't a clutch style.  The biggest disadvantage to the cone style is that they aren't really rebuildable but a new one can provide many years of service before needing a rebuild anyway.  The clutch type can also give better rearend performance but on a primarily streeet driven car would you notice it?
The limited slip will certainly light both tires and allow for good cornering.  If you are considering a gear change as well, then this is definitely a good time to do it.  3:55 makes for a very nice street performance ratio.  There is an air lock system out there but I think it's expensive and a little more involved to put in.  I don't know that for a fact though so a little more research would be in order.

[andy74]

i have the clutch type sure grip in mine,and i love it!i had a locker in a ford pick up that i built in the late 80s,and it was a fun ride in a strait line,but really noisy and grabed a lot in turns

[Mike DC]

 
Cone-type diffs are as strong as anything but they're non-rebuildable.  Clutch-type diffs are best of the classic LS options.  I think Auburn makes a good one that's adjustable when you set it up for different preloads & stuff.

Lockers are great for gravel-road fun, but not much fun for smooth & comfy street cruisers.



I'd love to have one of the electric locking diffs they're starting to come out with.  (Probably not available for the 8.75" rearend yet.)  The ones that are LS all the time, and then it can be fully spool-locked with an electric switch.  Sounds like a lot of fun if you don't run tires that are too grippy and kill it.

     

[Chatt69chgr]

A clutch type suregrip would be the best.  These were discontinued by Mopar around the 1970 timeframe and as time went by became very hard to find.  They were replaced by the cone type suregrip.  Fortunately, the clutch type suregrip is available again new.  A trip around the internet will turn up multiple sources I would think.  And as others have stated, the clutch type can be rebuilt.  The clutch pack as well as the thrust buttons are both available from Mopar.  The cone type actually can be rebuilt maybe once or twice, although it was never intended to be rebuilt, by machining off the ends of the cones.  I don't know if there are services that do that on a regular basis or not.  I read on here that there are articles on the net showing the procedure.  This might be a good way to go if you already had a cone type as new ones cost around $500.  But if you are going to spend the money to buy one anyway, I think I would just save my $$ and buy a clutch type.  And who knows, maybe you can score one at a junkyard or find someone that is selling one used.  I found one at a junkyard a couple of years ago for $100 out of a car that I bet a lot of folks walked past and discounted as not having one.  But, lo and behold, it did.  One thing I have discovered is that Mopar guys tend to hoard parts.  So if you can find out where the local Mopar guys hang (like at the local dragstrip) then the thing to do is to go there and make some new friends.  Then mention that you need a suregrip.  One of them might have one or know someone that does.  Another way is the car cruise-in.  The season for these is just starting.  Go out there and talk to the Mopar guys that show up.  Might get lucky.