A spool v.s. a Suregrip

[mrbill426]

For "Project '72 'Cuda", we are trying to decide what to do about the rear axle. It has an open "489" 3.23 right now which is fine for the highway, but as discussed before (in a "cam" thread) we plan to do some performance upgrades for occasional ET racing.

We have a driver '64 D-body that has a "742" Suregrip (also 3.23), and have thought about doing a guts swap between the two cars, but that looks like a bunch of work, and would still leave us with the high gears. Searching around for a powerlock type Suregrip has been a nightmare as they fetch a pretty high price to begin with, then you have to rebuild them.

Not knowing the projected cost, would we be money ahead to just find another empty (or open) 742 or 489 case, and install a new ring & pinion (3.91-4.10) with a spool? What does that entail besides the gears and spool? Are the same ratios available for both cases?

We have no problem with doing a 3rd member change before going to the track.

Thanks

[ehostler]

Try Randy's. They can set you up with a great 3rd member for a very good price.

[eric414]

IF you go with a spool make sure you get some aftermarket axle,but for street i wouldnt go with a spool

[mrbill426]

Right, pretty tough to go around street corners with a spool.

I called "Randy's"..., and was quoted $950 for a "spare" 742 with a suregrip and 3.91 gears. Yep, that E Body/D Body differential swap is looking better all the time! Unless I can find a bare 742 or 489 case and put in an (I expect much cheaper but stronger) Spool.

Bill

[dwc43]

Don't use a spool on the street. It will quickly wear the tires and it's just plain unsafe. Can you say swap ends if you get caught out in the rain with it?

[ohioDemon]

i agree, a spool on the street is an accident waiting to happen.

[wedge440]

Look on ebay or local for another case, buy the gear you want, install new bearings, seals and spool....
489 and 742 has gears that are very close to each other.....
You can drive a spool on the streel with stock axles if there in good shape...Lower your tires down a few pounds, that will let the side walls give as you go around corners. Tire wear will still be faster then normal...

[dwc43]

Stock axles wont survive in the street with a spool. You'll either strip the splines off of them or snap them right at the axle bearing during a hard turn. Get a sure grip for the street, it's all you need.

[wedge440]

Originally posted by dwc43
Stock axles wont survive in the street with a spool. You'll either strip the splines off of them or snap them right at the axle bearing during a hard turn. Get a sure grip for the street, it's all you need.

Stock axles will survive on the street, been there, done that. 2 years on stock axle and a spool..mid 11`s and lots of street driving before I got my SG.

[Mr.Abuse]

Get The Spool...I've Used One for 10 Years, No Problems Or Accidents...lol...As For Excessive Tire Wear, I Use Up A Lot More Thread Leaving Stop Lights Than Turning Corners..

[eric414]

I'm sure someone has ran stock axles with a spool but its not a good idea and some people are just lucky sometime.i am lucky so far running a stock sure grip and axle in a low 10 sec car but going with a stool hopefully before the sure grip shoots out of the back of the housing.i only go up the street a few time a year at a local 60's hangout.

[72Challenger]

A lot of people run seriously beefed up engines on the street using a stock driveshaft, U joints and rear end yoke, without a driveshaft loop. That doesn't mean it's a good idea.

[eric414]

Yeah i run a high horse power small block with the rear end parts all stock.But think about this.you can run a beefed up engine as you said on the street but want are the odd on breaking up parts on the street vs track.On the street my car spins all day long but on the track hooks hard.can you say breaking parts.oh and i dont run a loop which isnt a good idea is it.

[72Challenger]

eric414, you're right about the street being a lot more forgiving than the track. But I broke a U-joint on the street, without a loop. Thankfully it was the rear and not the front. Not a good idea, correct!

That was about 25 years ago, I have never since built up an engine without putting on a driveshaft loop. I consider that to be mandatory safety equipment, like wearing a seat belt. Hey, you really should put one on. The $25 is a lot cheaper than the damage from not having one!

[mrbill426]

Wowee, a lot of replies to this, I quit getting emailed "reply" notices so I thought it was a dead issue. I appreciate everyone's input!

We plan to road this car a lot when the weather is nice, to shows, cruises, etc so retaining the 3.23s (open) is probably a good thing for that. For the track the search is on for a unit to swap in as needed, either with a spool or a clutch type S.G.. and 3.91 or 4.10 gears. The 742 (clutch S.G.) is right there in the '64 Imperial, but even if we use it we are still shy one differential to make both cars run. We could do a LOT for the cash Randy's wants for a unit, not worth it for the occasional type use we are planning.

Or.... we back off a bit and put the Imperial's 742 in the 'Cuda with new gears (say 3.55), and put the open 489 in the Imperial, and run slower at the track. THEN, there is the issue of the yokes, the 742 (Imperial) is bolted to a Constant Velocity drive shaft, I doubt the 489 in the 'Cuda has the same yoke. Is that a biggy, or are yoke swaps between those carriers a snap??

Are you all sick of me yet?

[ehostler]

Randy's may not be cheap, but they are less expensive the the competition. At the same time, they have about the best quality. If you go with a Randy's setup, you have the confidence of knowing that it is all new (except the housing) and that it was done right. For a little more, they can set you up with a custom housing that has the bearing braces/girdle built in.

[mrbill426]

Thanks, I may call them back anyway, because I failed to inquire for a quote on a housing/gear/spool setup, I would think that would be a LOT less than a unit with a S.G..

I felt a bit rushed in talking with him (Randy's), he put me on hold about every min and and kept telling me how many people he had "waiting". Not a place to call with tech questions, more suited for "in the know" folks who are ready to buy I guess. Such is the way I suppose. Waa waa waa

Again, this is for occasional trips to the track. I could opt for a "cone", there are tons of those out there, but I have been told to avoid them as you don't know how much life is left in them and they can't be (easily) rebuilt. As "iffy" as they are, they too are pricey I think.

[Luther]

I felt a bit rushed in talking with him (Randy's), he put me on hold about every min and and kept telling me how many people he had "waiting". Not a place to call with tech questions, more suited for "in the know" folks who are ready to buy I guess. Such is the way I suppose. Waa waa waa

Uh, give them a break. Call back when they are not busy or have all their staff in. I have dealt with them before and thought they did a good job of answering my questions and are technically competent.

You ought to try dealing with my insurance carrier. That can easily turn in to a half day ordeal working thorough their computerized phone system and worthless service reps before finding an intellegent human being to talk to.

[mrbill426]

You are right about that, Luther, most companies make you go through a dozen push button options before they even offer (if at all) to let you talk to a real human. The guy (Mike) seemed very competent and polite, just really rushed. I told him they needed more operators, he replied about answering phones for sombody else too. He did say that the 742 case was the way to go for me.

Anyway, I'll give them a shot about a "spool only" setup and see what they say. I'm gonna look for a bare housing too, maybe I can gather the pieces and put it together myself. I take it the spool is just held in the case with (adjusted) carrier bearings and that's it? All I need is what I have mention plus the ring and (shimmed) pinion??

Are all the 742 and 489 carriers 30 spline, meaning the axle diameters and splines in the '64 Imperial and the '72 'Cuda are the same?

Bill

[ehostler]

The primary difference between the 742 and the 489 is the pinion stem diameter. The 489 uses a larger diameter, however it tapers down to the same size as the 742. That taper can be a weak point.

With a proper build, you will eliminate the crush sleeve that is in the 489.

They both use the exact same axles.

[mrbill426]

Cool then if I am "hearing" right, I should be able to swap the yokes between the two cars without a problem! That's assuming that the splines on the two pinions are the same too.

The big headache on that '64 Imperial axle is that the outer ends of the axles are tapered and keyed, the hubs/drums being an interferance press fit. I had one hell of a time getting them off when I did a brake job last year, even with the correct puller. You are suppsed to tighten the forcing screw into the axle center then hit it with a hammer..."No way Jose", it took an pneumatic impact on that screw to pop those hubs off!!

The taper of the 489 being the weak part may be why Mike at "Randy's" recommended we use a 742 in the 'Cuda.
I have seen "reusable" sleeves on the market for the 489. By "proper build", do you mean using one of those, some special spacer, or shims?

Bill

[ehostler]

Yes, I am refering to the use of a solid sleeve (randy's has them), instead of a crush sleeve.

[toad490]

Excuse my ignorance but what will the solid sleeve do and would it be ok to run on the street? It would be for my 70 cuda, runs high 12s, 3.91 489 sure grip. Its our daily driver so it has to work on the street.