Replacing Rear End: '65 Dart GT

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EDC

EDC

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Disclosure: I am a novice at this.

I want to replace the rear end on my 1965 Dart GT convertible. Moving up from the 7 1/4 would be nice, but not essential. I saw a 1973 Demon advertised at a yard about 90 minutes from where I live. Before I make the drive, I am wondering:

1. Will it fit easily?
2. Will it be large bolt pattern?

Anyone know? I've been trying to research this on-line, but most of what I've found doesn't even acknowledge the existence of the Demon in 1973.
 
IF it's a 73 and IF it had disk brakes, then it will be large bolt pattern (grab the front brakes too if you can). Unless it was 318 manual transmission or 340 car it will most likely still be a 7 1/4. No gain there other than the LBP. The gear ratio might be worth considering. It would be a step backward to replace 3.23's with 2.76's.
 
Thanks for the replies. My front brakes have already been converted, and the front has the LBP. Thus the incentive to get a LBP rear, even if it's just a band-aid while I look for something beefier. Truth be told, however, with the way I expect to drive this car and the stock slant six under the hood, I can imagine the 7 1/4 working just fine.
 
ddart, it seems the '73 has a 7 1/4 also. Would you still expect the driveshaft to be different from the '65? Any other compatibility issues? Not sure, but I think the '65 driveshaft has a universal joint setup that changed in later years.
 
EDC said:
ddart, it seems the '73 has a 7 1/4 also. Would you still expect the driveshaft to be different from the '65?
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Yes, it's definitely different - see next comment

[quote-EDC;1970734725] Any other compatibility issues? Not sure, but I think the '65 driveshaft has a universal joint setup that changed in later years.[/quote]

The 65 has the ball and Trunnion set-up which was the last year for it. 66 and later went to the u joints in the front
 
Gotcha. So if I'm swapping my '65 7 1/4 for a '73 7 1/4, do I need the '73 driveshaft? Will I be looking at any other changes and/or parts needed?

BTW, I know the downside to the 7 1/4, and I get why many would say this is a waste of time and money. That said, I'd like to get the car on the road with matching wheels. But finding a beefier rear isn't easy, so if this gets me driving quickly, I'll take it for now.
 
If the donor is a Dart Sport, then the driveshaft will probably be shorter than the 65 driveshaft. If keeping the B & T on the 65, it might be easier to shorten it after you get the new rear end in place and see if it needs to be shortened.
 
If you swap in the 73 7 1/4 rear axle, you will just re-use your 65 drive shaft. No need to change. You would have to have the drive shaft shortened if you installed a larger differential (which is no big deal anyhow). The axle assembly swap is a bolt-in.

What you probably can't do is just slide the big bolt pattern axle shafts into the 65 housing. If your 65 axle has 9" brakes, as most slant cars did, the housing is a different width.

Are the gear ratios similar between the axles?
 
C130 Chief said:
If you swap in the 73 7 1/4 rear axle, you will just re-use your 65 drive shaft.
Click to expand...

I think the 65 driveshaft would have to be shortened due to the different wheel bases - 111" for the 65 108 for the Dart Sport. Only way to be sure is install the 73 housing and fit the driveshaft.
 
Not sure about the gear ratio, unfortunately. It's a 318 engine, fwiw. I was planning on getting the brakes with the rear end, and it sounds like it wouldn't hurt to grab the driveshaft while I'm at it.
 
EDC said:
It's a 318 engine, fwiw. I was planning on getting the brakes with the rear end, and it sounds like it wouldn't hurt to grab the driveshaft while I'm at it.
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If it's a 318 car, I think it would be a LBP rear end, whether a 7.25 or 8.25.
 
I got a look at it (via pictures) and it's a 4-door, so I don't think it's a Dart Sport, I think it's a Dart Custom (it's got the black vinyl top). With all the trim gone, it's hard for me to be sure. But I don't think it really matters. It should still be a 7 1/4 LBP. If anyone knows otherwise, let me know. VIN is LH41G3R284349, in case anyone knows about decoding those.
 
EDC said:
I got a look at it (via pictures) and it's a 4-door, so I don't think it's a Dart Sport, I think it's a Dart Custom (it's got the black vinyl top). With all the trim gone, it's hard for me to be sure. But I don't think it really matters. It should still be a 7 1/4 LBP. If anyone knows otherwise, let me know. VIN is LH41G3R284349, in case anyone knows about decoding those.
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Since it's a 4 door, your 65 driveshaft should bolt right in (same wheelbases). It could be a 7 1/4 or an 8.25. Got a photo of the back side of the pumpkin area? That will tell the story what it is for sure.
 
Just swap the axles, you would want to replace the axle bearings and seal either way. If the rear end is a 7 1/4 lbp, the axles will unbolt and bolt directly into the housing you already have. Done the swap many times. converting from sbp to lbp
 
7 1/4 rear will swap over, no driveshaft needed. Lbp axles will swap over too.8.25 rear will have lbp and will need your B/T driveshaft shortened as its snout is longer than your 7 1/4. Gear and pinions swap within the same rears too, yours howling? A slant will not hurt a 7 1/4 unless its built.
 
Hey Pishta - your PMs are full - got a tracking number for you
 
I'm 99% sure you can't just swap axle shafts between early SBP housings, and late BBP housings. you have to swap the whole shebang. The axle housing ends on the later 7 1/4's have 5 bolts, like an 8 3/4 or 8 1/4....where the earlier 7 1/4 housing ends only have 4 bolts. I'm referring to the bolts that go thru the axle retainer, that you put the nuts on, to hold the axle in. I have also heard that the splines on the axles are different, and the bearings are different. I don't know about that(splines and bearings) for sure, but the person that told me is an experienced A body guy. To me, it's just as easy to swap the whole thing. Just be careful with the u bolts, and slather them with PB Blaster. Good luck.
 
if the rear end is out of a 318 4-door I'll almost bet money it has 2.76 gears. Your 65 rear had 3.32 or 2.94 gears. My 65 came with 3.23.
 
If it's a 2.76, that's not all bad for me. My goal is a reliable, fun, and somewhat economical cruiser. With a stock slant 6 and automatic transmission, acceleration won't be it's strength regardless. Now that I'll have matching wheels, it will be time to buy tires, so I'm open to suggestions on sizing.
 
64DartGTinAZ said:
In case you end up needing to change your driveshaft, you may want to consider this:

http://www.earlycuda.org/tech/ujoint.htm
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That is my car. You don't need to do that conversion, as long as your B&T joint is good.

Any "A" body rear assy will bolt into any "A" body car. A 7 1/4 will fit bolt for bolt, with no mods, into any "A" body that had a 7 1/4. The original driveshaft for the car is used. The driveshaft only needs to be changed or shortened, if changing to a different size housing (8 1/4, 8 3/4 , etc). The 7 1/4 large bolt pattern axles will not fit the small bolt pattern housing. The bearings are larger and the bearing retainer is different. I have never checked to see if the SBP bearings and retainer can be put on the LBP axles, but I don't think so. To upgrade to the LBP the complete assy needs to be changed, but it is a bolt for bolt swap.
 
Charrlie_S said:
That is my car. You don't need to do that conversion, as long as your B&T joint is good. Any "A" body rear assy will bolt into any "A" body car. A 7 1/4 will fit bolt for bolt, with no mods, into any "A" body that had a 7 1/4. The original driveshaft for the car is used. The driveshaft only needs to be changed or shortened, if changing to a different size housing (8 1/4, 8 3/4 , etc). The 7 1/4 large bolt pattern axles will not fit the small bolt pattern housing. The bearings are larger and the bearing retainer is different. I have never checked to see if the SBP bearings and retainer can be put on the LBP axles, but I don't think so. To upgrade to the LBP the complete assy needs to be changed, but it is a bolt for bolt swap.
Click to expand...
Not trying to hijack this thread but this raised a question for me. I am going to an 8 1/4 on my 65 Dart so I will need my shaft altered, at that point should I just do the conversion to a u joint? If not how do I know if my b/t setup still has plenty of life before I pay to have it shortened?

Thanks
 
If you need to modify the shaft, anyway, I would opt for the conversion. The driveshaft shop I use says it is easier/cheaper, to build a complete new shaft, rather then modifying the old shaft. The only thing they use from the old shaft is the rear U-joint "ears".
 
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