Help save 7 1/4 !!!!

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one mile

one mile

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I want to keep my Daughters '65 Barracuda as mechanically origional as possible but I have been reading on here that the factory rear is Trash. It's a Sur - Grip or whatever you call it. Does anyone make H.D. Spider Gears for these things? I assume that is the weak spot correct me if I am wrong. I REALLY need help.
 
I got this rear end from Scampin (Great Guy to deal with) and now I am going through it so it will not give her any problems in the future. It's a 273 Auto and I am trying to use all of the "UPDATES" I can get off of here (GREAT FORUM) for the Car and it will be more of a "Resto-Rod" I guess you would call it more than a restoration (Backyard kind). Doing all of the Safety updates I can.
 
I have run 7 1/4 rears pretty hard with the regular open end. The sure grip is much stronger at least in the spider gears. If you are not drag racing the car on a prepped track it should last fine.
 
I don't know about HD spider gears, but I do have a complete (drum to drum) 7 1/4 that I will give you for free....so you will have a spare. It came out of a 70 Duster with a / 6, so I'm reasonably certain it's a one legger. If you want it, just come get it next time you're in Asheville.
 
The only problem I have had is the rear wheel bearings only last about 30 years. With a press, the change is easy and the result is a very quiet rear end.
 
If it's a stock 273 a 7.250 with a sure grip unit might hold up ok.
 
A friend of mine still has his 7 1/4 behind a 340 in a Demon. Never had an issue, granted if he had sticky tires and pull hole shots all the time there might be. Just take it easy with the cheese whiz and you'll be all right.
 
Thanks for all the reply support ! Thanks JDMOPAR for the offer but I will have the spare I pull out of it. All I have heard is how weak they are...its good to hear a few positive reports on how Strong they are. Just so I will know, what "Gives up" when they do break ? Spider Gears ? cross Pins ? or does the Clutch and Spidergear Case split or crack ? Thanks !
 
That 7 1/4 will do just fine if driven normally. I have had several in a past life and I never broke one, and I beat on them mercilessly.

If it were in a high HP application, and hooking up then you would have serious problems.
 
i too will voulge for the 7 1/4 behind the V8 if it is not abused and your not trying to break it, it will live. and yes i have left a couple of nice black marks with mine lol
 
I had a 7 1/4 sure grip behind my 360/727 for almost 3 years before I got my 8 3/4... and I have to agree, driven normally it will be just fine.. Even some fun spirited driving wont hurt (didnt hurt mine, and I wasnt always kind to it) .. now Drag racing, high horsepower and sticky tires, you'd kill it LOL
 
I currently have a 7-1/4 sure grip in my 64 Barracuda. The original. I have broke 7 open 7-1/4 rears without abusing them. Seems that snow and ice are a death wish for them. If you have one wheel on ice and it spins and then suddenly gains traction bad things happen. The spider gears, cross shaft and carrier are all waek. On mine the cross shafts break out of the carrier. I'm sure with moderate to high horsepower the 7-1/4 will give up pretty easily on dry pavement, especially if one wheel spins.
I don't really "hot rod" my car with the 7-1/4 in it but I don't baby it either. The engine is healthy enough to roast tires on occasion, the shift kit provides some nice solid gear shift chirping and the sure grip has held up. The good news for you is that according to my experience the 7-1/4 sure grip has the ability to stay intact far better than the open unit!
 
Stock 273 auto with no shift kit will have a sure-grip 7 1/4 last for the life of the car. Behind a 4 speed it wont however.
 
one mile said:
Thanks for all the reply support ! Thanks JDMOPAR for the offer but I will have the spare I pull out of it. All I have heard is how weak they are...its good to hear a few positive reports on how Strong they are. Just so I will know, what "Gives up" when they do break ? Spider Gears ? cross Pins ? or does the Clutch and Spidergear Case split or crack ? Thanks !
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I don't think I would go so far as to use the word "strong" when talkin about the 7.250....cause....well.....they ain't. They are in fact, weak. But if you drive as outlined and it is only a stock 273, the rear axle you have should hold up.
 
I would Ditto what others have said about 71/4 rear my 66 cuda was drag raced for many years in street class with its original 71/4 rear never had any issues with it. car ran in low 15/high 14's very consistant. I only went to 83/4 rear when moving engine hp up and trying to get to higher class racing with that car. My current 65 formula s cuda has same set up as old 66 did recently rebuilt rear to allow 14 inch tires but kept original set up as it will be a street car no more drag racing at this time. Those rears if maintained last forever and have no issues with v8 318/273 modest hp! Good luck enjoy the ride I love my early A body Cuda!!!!
 
I currently have a 2.94 ratio open end 7 1/4 in my beater 70 dart. Living fine behind a hopped up 318 and o/d four speed. I drive it hard but don't dump the clutch. I have never broken a 7 1/4 and besides the four speed car I have never babied them.
 
Out of all the a bodies I have bought for parts in my life time I never got one because the rear end had gone south. Good rear ends for the original application if it is maintained. Maintance is the life of anything.
 
Oklacarcollecto said:
Out of all the a bodies I have bought for parts in my life time I never got one because the rear end had gone south. Good rear ends for the original application if it is maintained. Maintance is the life of anything.
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I agree, the only 7.25 i've seen that took a dump was a kid with a 70' 318 Duster that had a fetish for doing donuts in every parking lot he ever came across...lol.
 
I have never broke a 7 1/4 and abused quite a few.
I did blow the spiders in a 8 3/4 behind a slant with a 3 on the tree.
 
SpeedracerX said:
..now Drag racing, high horsepower and sticky tires, you'd kill it LOL
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Ditto. What many people don't realize is that the max forces on the brakes and rear-end are pretty predictable. There is a "force limiter" already built in, which is when the tires slip on the road. It is torque that would break a brake mount or rear gears (HP does add heat to gears, but not at low speed). Unless you have large diameter, sticky tires, that you softened up by a burn-out, the limited force you can get from the tires should not endanger a 7-1/4 rear. You should be thrilled you have a sure grip. If you don't want it, PM me. In sum, if it ain't broke, ...
 
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