is there such thing as a posi 7 1/4 rear end?

[74 DART SWINGER]

I was just woundering becuase on ebay the Item number: 2442925026 . He says it has 3.23 ratio. If you go to ebay motors, search, then type in mopar, and then go to denver, colorado. You will find it on the last page. thanks

[rumblefish360]

Yes, I had 1. Rid yourself of this rear with any upgrade you do on any engine.

[74 DART SWINGER]

Would 3.23 gears help over 2.76? and its a posi so it should help...but itll probably break if I get my hopped up 360 in there.

[pishta]

Had one on my first '65 340 cuda. I think they were better than 2.93's (3.23, small chance it was a 3.55) because I had to replace it (340 was too much, pinion spun the teeth off and took a bite of the ring gear too) with a 2.93 peg legger. What a dog out of the hole!!

[74 DART SWINGER]

Do you thin it would launch better out of the hole? are they tuffer then the wimpy 2.76 open? DO you think i would get better 0-60 time?

[pishta]

better 60 foot times but not as strong as the wimpy 2.76 (which still has a larger ring gear)

[74 DART SWINGER]

Would a stock 318 break it?

[pishta]

I think you would be safe. It lasted behind a Commando 273 4bbl for 30 years and my 340 for 2...

[71383bee]

I am with rumblefish here. For the time it will take you to pull your axles, drop the center section and rebuild it with the 3.23 ring gear and put it all back together all so that it will break on the 3rd pass with any motor that has got some decent balls to it it is much easier to find a good axle and use it. The 8 3/4 is the end all best axle for what you are looking for. If you can't find an A body one then get a B or C body axle and have it shortened by a good suspension or hot rod shop. With a center section that just drops out they are a cinch to swap and are extremely strong and versitle with gear selection.

IMHO...Don't wast your time on that crappy 7 1/4"

[rumblefish360]

A cheaper way out is an 8 1/4 rear. Set it up with a new sure grip unit from MoPar, Arburn, etc... and give it the ratio you want.
8 1/4 rears are a staple in A body cars. The rear is good to 400 HP in an everyday application. If you beat on it, the 8 3/4 is the ticket.

Rear ratio;

The diff. between 2.76 and 3,23 gears is an OK upgrade. There will not be a BIG difference in the out of the hole feel. You will notice it, but it's not a real get up and go feeling.
The last of the street gears with good mileage and good get up and go would be 3.55's. After that, the jump to 3.91 is to much.
The 3.23 ratio is the best for mild engines, mileage/performance in mild engines.
Your 0-60 times will drop. You really won't feel it much, but it will show on the clock.

[MY340]

I agree with Rumblefish as the 8.25's are more plentiful and cheaper than an A-body 8.75 and would be plenty strong for your application.

[74 DART SWINGER]

Would a ford 9" rear end be good?

[rumblefish360]

It would be plenty strong.
But heres the draw back(S)

Must be narrowed. This requires custom axles.
Then you need to take out a welder to weld on spring perchs for the leaf springs in there new location.
If you do not get them spaced right, your welding agin after you install it., Also, the angle they sit at is critical. Do it wrong, your welding again after you take them off.
Now you need a new drive shaft with custom parts to mate the Ford U-joint to the smaller MoPar U-joint. Then it must be cut to size and balanced. (This step of re-sizeing may be needed with the 8 1/4 swap, but at a fraction of the price. Why, still useing all MoPar parts instead of 2 company's parts for odd ball combo's.)

If you think you need a stronger rear for more power, the 8 3/4 will take whatever you dishout. The most work you do is upgrade axles.

[71383bee]

People think that the ford 9" is the greastest thing since sliced bread. Every hot rod chevy customs one in mainly because the GM rear ends are junk. The Chrysler 8 3/4 is every bit as strong as the 9" was and if you really need to go stronger then the 9 3/4 dana is out there too. Ma Mopar new what they where doing...

[dwc43]

Originally posted by 74 DART SWINGER
Would a ford 9" rear end be good?

The 9 inch is very strong and we could set you up with a full floater 9 inch but it's costly but we can get it in any lenght you want.

Rumble is on the right track withthe 8 1/4. One from a Dakota will fit and most likely has a 3.55 sure grip if you get one from an auto tranny truck and maybe get lucky and get you a 3.91 from a v 6 auto tranny truck.
The 1/4 is ever bit the equal to the 3/4 in strength, but it takes longer to change gears. That's why we use them on our oval track race cars. The 3/4 need a moser back brace once the hp gets really high up there. It has housing flex problems that break caps and strip axle splines, but you have to really get up there in hp to start doing that and the back brace prevents most of it.

[dave571]

Go with the 8 1/4. You can probably find one with a 321 ratio(not 323 in 8 1/4) for around $50.

It will bolt straight in, still have big bolt pattern, be plenty stong, and only need a sure grip carrier for an upgrade.

Great part, great price. Man I feel like I'm selling something here

[dave571]

I'm questioning 9"'s as well.

A ford guy I know has destroyed about 10 carriers.

They aren't all the same. There are different versions of 9", just like there are different versions of 8 3/4 (741,742,489, blah blah blah)

They aren't al the same, and they're not all bullet proof either.

Then again, What is??(bulletproof)

[dwc43]

True, nothing is really bullet proof is it. But I have never grenaded a A727, A833, or a 8 3/4. So that says a lot about them cause I have punished some real good over the years. As for the nine ccase center sections, I can get three different types of those things too if some one wanted one. Still thinking about making a full floater 8 3/4 with a back brace for us to R&D at the track and sell. It's not really hard to make at all either.