Drag Racing With Clutch Type Sure-grip

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72DMag

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How many burnouts/ 1/4 mile passes can a clutch type sure grip take in a street/drag racing application? Building 76 volare ~3400lbs with 742 case and a 318, 904 with low gear set, 3500 stall converter. The engine should have about 400hp. Plan to run 9" cheater slick maybe 10" if can fit it. Hoping for 12.00 ET. Yes I can go with spool but would also like it to be streetable and I have stock 30 spline b body axles in it.

Being a 318, the rear won't see near as much torque as a big block. But for racing at a track maybe it will need tore apart and checked often?

(Tried doing a search but couldn't find an answer. If previously discussed please attach thread link thanks)
 
As long as you launch straight and true and both tires get equal or real close to equal traction, probably as many passes as you can throw at it. If that's a Dana Powerlock, they ain't a light duty piece.
 
....btw, the Ford 9" I am building up for Vixen has a 31 spline spool in it. I've run a few on the street before and they do fine.
 
@RustyRatRod I know a couple guys that do power tours and run their car on the street with spools.

But I do plan for this car to see more "practical" street use like parking lots and tight city turns. So kinda leaning toward the clutch type sure grip for that reason. I have one laying in a 741 case currently. Thanks for Input on that bud
 
I have a 3700lb car I drag race with slicks and a 3.91 clutch SG. What always happens is the spider gears or ring gear break around 400 runs. (4 times now) The SG always spins both tires just fine. I don’t think it’s hard on the clutches going in a straight line.
 
I would use your clutch suregrip and not worry about it at all. I never broke mine when I was running one, in a 3400lb 440 bracket car. Still using stock axles with slicks, too.
I will admit that I did move up to a dapco locker during the most recent gear change. I'm not gonna put any more money in the 8 3/4. When I make more power, gonna just step up to a dana.
 
They do break. I recently bought a used unit that looked ok but exploded after three passes behind a 450 ish Hp 340. Apparently it came out of a 12.0 360 Dart. It was a tough pill to swallow. Whatever you choose to do, I’d buy new.

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@340GTSDart Based on the springs in your photo that is a cone type suregrip. I wouldn't drag race those at all! and I'm impressed it lasted you that long. The cone types are more for traction in wet and snow conditions. Meanwhile the clutch type are beefier IMO and don't tend to explode like you see.

As stated I'm running clutch type suregrip. Thanks and OUCH!
 
340GTSDart said:
They do break. I recently bought a used unit that looked ok but exploded after three passes behind a 450 ish Hp 340. Apparently it came out of a 12.0 360 Dart. It was a tough pill to swallow. Whatever you choose to do, I’d buy new.
Click to expand...

You bought a USED race car diff.
You bought a USED race car diff ! ! !
 
Yep, that's a cone type, significantly weaker as a lsd than the clutch type. They can be rebuilt and tuned up, if they aren't exploded by busted gear teeth in other rotating teeth!
 
72DMag said:
@340GTSDart Based on the springs in your photo that is a cone type suregrip. I wouldn't drag race those at all! and I'm impressed it lasted you that long. The cone types are more for traction in wet and snow conditions. Meanwhile the clutch type are beefier IMO and don't tend to explode like you see.

As stated I'm running clutch type suregrip. Thanks and OUCH!
Click to expand...
I didn’t know that, thanks for the info
 
413 said:
I have a 3700lb car I drag race with slicks and a 3.91 clutch SG. What always happens is the spider gears or ring gear break around 400 runs. (4 times now) The SG always spins both tires just fine. I don’t think it’s hard on the clutches going in a straight line.
Click to expand...
I have a 742 case 3.91 clutch sure grip, factory carrier. Can you tell me where you are Getting the spiders.
Both SGBARRACCUDA and I looked hi and low for them, had to buy used
FYI, Dr Diff has Dana clutches that will work in 8 3/4 with slight modifications.
 
The trouble is, there are no new clutch type. The auburn is a cone, and they admit it's not rebuildable (even though it is). That leaves the gear types, that most LOVE , but I have heard of problems. Then there is the dapco (Detroit automotive products co., known as the Detroit locker) VERY strong, but noisy, and has its quirks. Also, there are lockers that can be put in an open carrier. I haven't tried those, but I'm going to, in a nine inch, cause nine inch posi's are even worse that the 8 3/4 cone.
 
Does ARB(?) make a car diff locker? Locks up on demand with air pressure. 4x4 stuff.
 
Powertrax Lockrite in an 8 3/4. If you forget it's there and punch it in a corner you'll immediately remember. Noisy when doing tight turns but nothing too awful
 
72DMag said:
@340GTSDart Based on the springs in your photo that is a cone type suregrip. I wouldn't drag race those at all! and I'm impressed it lasted you that long. The cone types are more for traction in wet and snow conditions. Meanwhile the clutch type are beefier IMO and don't tend to explode like you see.

As stated I'm running clutch type suregrip. Thanks and OUCH!
Click to expand...

Cone Style Sure-grip only has 2 spider gears and one cross shaft.

Clutch type Sure-grip has 4 spider gears and a 4 post cross shaft. More than twice as strong as the Cone style.

Twice the tooth grip on the side gear teeth also.
 
I've ran a spool for I think about 8 years now... When I drag raced the car on a regular basis it always launched pin straight. I mostly City drive it now and I'm so used to it skipping a little going around corners or finding a little when I'm going slow and turning slow that I don't even really think about it much anymore.. much more inexpensive and never has failed me...
 
To the OP;
>Since nobody mentioned it, the Trac-loc/Tru-Trac/ clutch type
has 4 spiders, and two interlocked and floating crosspins. You can adjust the amount of slippage with the throttle. So then it becomes more or less an open diff under light throttle, but locks on full throttle and in-between, she also is in-between. This is a very very useful feature in town.
>The cone-type has only two spiders, and one smooooooth cross pin, full-round saddles when new, and a weak-azz retaining pin. When the cones stop working, that diff acts just like an open diff, and when you peg leg it, she turns double what the Speed-O shows. Which often overheats the cross-pin, and it welds to the spiders and shatters the lock pin. If you didn't seize it up too bad, you can still drive it. If the seizure busts loose, the next thing you know the now loose crosspin fires out the back . Well it tries to, but every one that I've seen it only made it part ways out, which promptly stopped the axles from turning................ which is not something you want to have happen at speed.
But if this diff hangs tuff; over the years, eventually the cross pin will hammer out the saddles into ovals, and break the lock-pin.... yada yada yada.
>I have a gathered a collection of these cone-types over the years, and fixed the wallered out saddles with brazed in bushings and new parts as required. Some of them have seen the hammer of my 367HO, on the street only, and some have seen my stock long-bloc 4bbl318. They seem to be holding up quite well. I seem to have about a half a dozen left. At the track, the two times I went; once I used a spool and once I used my clutch-type. I'm done with the spool.
Btw, that clutch type of mine is out of my BILs 66 Coronet. I pulled it out myself, back in the mid-70s. She has been in most of my more powerful SBM cars.
The cone-types are reserved for use in my 318 cars, or for hi-way gears. I tend to drive my cars into the ground, and pull the powertrains for re-purposing, and the bodies go to the shredder.

OOps I see George beat me off the line, again.
I have got to learn to type faster.... lol.
 
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