Rear End Question(s)

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19 Again..

19 Again..

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Alright I've been on this forum for over a year, and I'll have to say this is the best, seems like someone always has an answer. I haven't posted much because I didn't have the reasons until recently, but now I have my car on the way to putting it back together the way I want to (like so many in here have). After engine rebuild, transmission rebuild, working on interior currently. I noticed when I finally got the car on the road for a few test drives, the rearend is just whining like a woman who wants you to get to the Honey Do list and finish it!. So currently I have a 7-1/4" rear end under it... I know the absolute worst especially with a new engine. So my question is I found a Volare & Aspen with 8-1/4's in them.. Will they bolt up?, and will the driveshaft have to be shortened - lengthened? And will the yoke match up??
 
Well..... Looks like the 8-1/4's aint gonna work out.. Not that they won't fit the car, but my budget is just about completly blown for the rest of the year. So I guess I'll go to plan "B". Not the best plan by any stretch but..I'm just going to rebuild my 7-1/4" and keep my foot out of it for the rest of this year (famous last words...I know). So here's another question... Has anyone used a 3.55 or 3.90 gear ratio in a 7-1/4" rear end?? Heck they even make a set of 4.10's, (wonder how long those would last at the light on the street or the burnout box at the strip) Right now I have 2.79 and it's doggie on take off... gets up to speed okay, even good on gas.. But at this point I didn't work on this thing for gas mileage, I 've done it for fun! I can get a set of gears for $188.00 + shipping. Alot cheaper at this time than buying a complete rear end and probably still have to re-build it before I could install it.. So has anyone had "a reasonable" experience with a 7-1/4 they can elaborate on... I already know from first hand experience the abuse they can't take..
Thanks!
 
I think once you've priced gears, carrier and pinion bearings, and everything else required to rebuild a raer you'll be looking for another plan. I had a 7.25 that whinned like the horn was blowing from about 45 mph up. The previous owner had drove it that way so we did too for almost 3 years ( until the slant 6 died ). If you'll be easy on it , who knows how far it will go.
A 8.25 from an a-body should cost 299 or less if not sure-grip. You might even get the shorter drive shaft at the same time. Myself and others opted to change the front spring hangers shifingt the axle back 1 inch.
 
If I could find a deal like that, then I'd probably consider it. But it needs to be the large bolt pattern.
 
19 Again.. said:
If I could find a deal like that, then I'd probably consider it. But it needs to be the large bolt pattern.
Click to expand...

That's why I suggsted using the 7.25 for a while. The 8.25 will come along. I got mine for 150 bucks, 323 gears , from drum to drum.
Good things come to those who wait ? :)
 
I guess we all get a little ancxious and I'm the worst at reminding people " patience is a virtue". So maybe I'll just kick back "cool my heels" and wait for a good deal. Thanks Redfish, everyone on FABO is like the best!
 
I thought I heard that the 8 1/4 should come from OTHER than an A body car for the big bolt pattern on the wheels??? I have a 7 1/4 now and would like to get the 8 1/4 also. I guess a lot of us are looking to upgrade from the 7 1/4 these days.
 
I put an early B body 8 3/4 in my Dart. I bought the rear complete for 100 bucks, shopped around and found a deal on a suregrip unit and picked up a set of 3.55's, gasket set and new bearings for the center section. Put it all together for just a shade over 600 bucks.

It did take some time pulling everything together, but it was worth the wait.
 
I can get my hands on some Dodge Pickup trucks pretty cheap. I wonder if the rears from them would work. Might be the best way to go especially if you can swap rears and just resell the truck.
 
Not sure, you would have to measure the length. The early B is about 1.9" longer on each side than the A body rear, but it fit nicely. It's in the car in my sig pic.

You have to move the perches, but that was about it other than larger U bolts and shock plates. The 7 1/4 shock plates can be made to work by elongating the holes.
 
I guess for length the easiest way to check is to measure from the Tailshaft to the axle tube on both vehicles. If it's real close I bet you could take everything from the donor vehicle including the drive shaft. How exact does the length have to be??
 
I also think you should wait for the right one to come along... I was looking for almost two years for a suitable larger rear-end for my '70 Duster and finally just a week ago I came across a B-body 8 3/4" from a '67 Dodge Coronet. It has 741 case with 2.94:1 gears (just right for my intended road-race/cruising use) and factory Sure-Grip, from the looks of it is low-mileage and not abused. And the best part -- $340, and it was just 10 minutes from my home! Before that I was looking at modifying a 2.45:1 8 1/4" I got for free (with the stupid unique carrier) and swapping gears and diff but now I've saved loads of money and have an axle that is ready to go, just needs the spring perches relocated so it'll fit.

FYI all 8 1/4" rear-ends came with the larger 4.5" bolt pattern. Only ones with smaller 4" pattern were the '72-down 7 1/4" and A-body 8 3/4".
 
I got good news and bad news. Good news I might be able to help you. Bad news is you would have to come get it:p
I am heading back to MI this week and I will be pulling my rear end here in few weeks. I have no use for it but I also I never had car running with the rear end. Could be bad could be good. Its up to you if you want it. Its coming from a 73 dart sport. 7 1/4. Send me a message if you want to talk about it
 
I also have a 7 1/4 you can have ... but i am even further away. I have no idea whats gear ratio ... and no idea if sure grip .... All i know it was in a 67 dart.

Have patience and start digging in some junk yards ... I find 8 3/4's in the yards for 100 bucks .. usually out of big c bodies and cut the housings down and respline the axles.
 
19 Again.. said:
So are you saying they made a 7-1/4" suregrip as well? Or did I interpret that wrong... If so how can you tell if your own isn't a sure grip Too.
Click to expand...
They made 7 1/4's with sure grips also. Not very common though. You can tell if you have one by jacking the rear of the car up (wheels blocked please), putting the car in neutral and with the brake off, rotate one of the rear wheels. If both rear wheel turn the same direction, you have a sure grip. If they turn opposite directions or only one turns with the driveshaft, you don't have a sure grip. (or it's completely worn out) I think there are some upgraded side gears and spider gears available for the 7 1/4. Those are the weakest part of the rear so if you upgrade them, you should be able to drive normally without worry. If you're going to jump on it, all bets are off.
 
Thanks everyone!
MeMike I appreciate the thread to view, unfortunately I have 5 - 4.5 LBP, in mine currently, it would just put me on the hunt for 2 more rims and tires..

unknownsnake, the offer is awsome, however I travel quite alot. And finding time is my biggest issue...and I am unavaliable for awhile, so if someone else needs it please don't hesitate to make them happy..

I'm not one for excuses although it sounds like it...sorry. But I do have the time to wait and be patient to find exactly what I'm looking for. Like so many I have read about and seen their projects come to life built the way they invision it to be, and so will I.. But the generosity of the this group never ceases to amaze me... And for that I'm greatful.. I hope as I go along I'll be the one posting "hey I got one of those and it's yours if ya need it" And Thanks for all the info...
 
I am sure i wont pull it for couple weeks but keep my name in you want it. Im in no rush
 
You didn't say what car you were putting this rear in, but your pic is of a Duster or Dart Sport? Do you know if the Volare or Aspen have sure grips? If they do, I would go for that original plan. Not a direct bolt up, but a very easy change. You move the spring perches in a bit. I moved my rear back 1/2" by using a spacer block in front of the spring hangers. One of the members here sent me a step by step process, with pics to follow. Very easy.
I got mine from a retired cop car, sure grip 8 1/4, cop wheels, rear sway bar, etc.
One other benefit, if it is the Duster or Dart Sport, that wider 8 1/4 sure looks better than the hunched up 7 1/4 look!
C
 
Thanks "clhyer" My car is a 73 Duster, and I will have to go back to the junk yard and verify if they are sure-grip or not.. I will continue in my quest... But not affraid to wait,, I took a picture of it today here ya go...
 

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That's a beauty! Got that rare hood mounted tach too I see.

I'll see if I can get a couple pics of mine to show what the spacer block and 8 1/4 from the M body did. I think they gave it a great look & stance.
C
 
Actually I put the tach on it, MFS performance out of Evansville Indiana sells a generic tach.. I liked it so I got one..
 
I have an A-body LBP 7 1/4 that I can hook you up with for cheap and I'm only about 20-30 minutes down the road from you. PM me your phone number or email address if your interested.
 
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