7 1/4 rear end hold up?

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cowboyup1107

cowboyup1107

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I am going to be getting allitle $ to put into my 72 dart and am wondering if my 7 1/4 rear end woulkd hold up to 455hp and 500 lbs torque if babied. I dont have enough to get a motor and a rear end and am trying to do things in order but the conflict is im in a hurry to drive the car again. advice?
 
Maybe if you're really, really, really, really gentle. But even then, I've seen these things break behind stock /6's, granted, they're usually driven by idiots, but still.
 
i would at least go down to u pull n pay and see if there is an 8 1/4. i really doubt there is one there, but there are a couple of 84 le barons down there with 8 1/4 rears. measure them, they might be about the same.i am using my 7 1/4 with a 360/727 and its doing just fine, but i have half the horses you do. you can drive it around, but the second you really get on it , something may give.
 
You'll break it the first time to get it in gear and start moving. They are junk! Go get yourself an 8.75 or a Dana 60. Both will hold that power with no problem and will also allow for an even great increase of power.
 
I wouldn't expect a 7-1/4 to last behind a stock 273. There is a pile of seven of the sorry things behind my garage with the pinions ripped out of the carrier. And, these were from the days when my 273 engines were basically stock. If you go around a corner and one wheel is on ice or snow and it spins a bit and then catches solid traction a 7-1/4 will rip it's guts out. Even minor hot rodding that causes one wheel spin will tear them up. I do have a sure grip 7-1/4 in one of my Barracudas that has held up to minor power modifications though.
 
For a trip to a body shop, maybe,...but not for long,...definitly not for a daily driver,........very, very gently bud.
 
I'd buy it. Wield it up, get a center section from someone and have at it.
 
The weak link in the 7 1/4 is the spider gears. They cant take any kind of major jolt.As long as you dont hammer it from a stand still,or do and down shifting,or WOT it will be fine for now.
 
cowboyup1107 said:
http://denver.craigslist.org/pts/2790902848.html
I found this 8 3/4 rear end put has two holes poked in it nothing i couldnt weld up and alot cheaper then others Ive seen but its near impossible to find a sure grip drop out around here. what do you guys think of this? worth it?
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i bet if you flipped him 275 he would take it. those plugged holes are nothing to fix. i would grab it up. i will race you to it!! on your mark.. get set.........GO! lol
 
Be as gentle as possible and you can get buy for awhile, they are weak but it will get you around just no burn outs or hard acceleration or it's all over. A buddy of mine has been driving around in his 79 lebaron with a built 318 for about six months while he builds his 8 3/4 and hasn't had a problem but he doesn't beat it at all. Good luck and keep your foot out of it. lol
 
My bro in law put a camed up stock 69 340 w ported U heads in a 72 swinger w a 7 1/4 and 904. The rear spider gears broke 2 weeks into it and then the 904 blew a few weeks after installing the 8 3/4. Might as well do it all @ once or you will be chasing the weakest link. My bro in law was driving a little hard. If you have the power you will use it eventually
 
cowboyup1107 said:
I am going to be getting allitle $ to put into my 72 dart and am wondering if my 7 1/4 rear end woulkd hold up to 455hp and 500 lbs torque if babied. I dont have enough to get a motor and a rear end and am trying to do things in order but the conflict is im in a hurry to drive the car again. advice?
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So you're trying to tell us that you have 455HP and you're not going to jump on it even once? :) Like I've said in the past....those rears are like a grenade with the pin pulled... it's not a matter of if, it's a matter of when....
 
I have a 7 1/4 in mine with a 360 built from mancini not sure of the HP but I hammer down on it took it to the drag strip and everything and haven't had a problem...not saying it wont rip apart next time I get the car out.
 
aarong5 said:
I have a 7 1/4 in mine with a 360 built from mancini not sure of the HP but I hammer down on it took it to the drag strip and everything and haven't had a problem...not saying it wont rip apart next time I get the car out.
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i am not pro 7 1/4, buts it good to hear someone having a positive experience with one..
 
cudamark said:
So you're trying to tell us that you have 455HP and you're not going to jump on it even once? :) Like I've said in the past....those rears are like a grenade with the pin pulled... it's not a matter of if, it's a matter of when....
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This!!...:glasses7:
 
DusterKrazy said:
This!!...:glasses7:
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Part of the equation is how carefully you drive, gear ratio, and tire size- diameter and width- that being said I agree that you should swap the rear before driving.
I also experienced snapping studs off rear- watched my rear tire/wheel pass me and then the rear dropped asap- scary
 
Ok Ok im not saying that it will not go but i know what my dad and uncle have put them sop called pos rears though lol and only broke one and that was a slant 6 car lol ... now idk bout how much hp there pulling but my dad has a sb 4 speed dart that the motor it now gone but it was a beast when it was good mashing 5.0 all day long .. it would turn 14 flat now the other one was a 66 dart that turned 13 some thing and its not like they was ez on them .. now for my cars my old val had and still has one in it but thats th one my uncle tore up lol he had a hot 6 in it made two pass and on number 3 he let it all hang all u could here was boom crack crack clank clack tink tink and no movey lol .. so ya if ur pushing that much hp i would upgrade. if ur pushing 95 hp like i would be in my barracuda and drive it as a DD then i would not worry bout it .. but that just me good luck
 
cowboyup1107 said:
I am going to be getting allitle $ to put into my 72 dart and am wondering if my 7 1/4 rear end woulkd hold up to 455hp and 500 lbs torque if babied. I dont have enough to get a motor and a rear end and am trying to do things in order but the conflict is im in a hurry to drive the car again. advice?
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They broke behind a stock slant 6. The tow bill from your first drive will be a setback on getting a real rear end.
 
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