Rear end mounting question

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Tanman74

Tanman74

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I found a decent looking 8 1/4 rear from a '92 Jeep XJ and I'm wondering if it will fit in my '74 dodge dart or what modifications I need to make to it fit.
Car currently has a 7 1/4 since it's a slant car and I'm swapping a mildish 340 in it so I wanted to change the rear end. Specs on the 8 1/4 is that it has 3.55 gears and has been welded.
 
A welded set of spider gears isn't good for a street car. 65'
 
Yeeah, I just watched a video of why NOT to weld spider gears lol. I put an wanted ad up in classifieds for a rear that'll bolt on but I'll still stalk marketplace.
Thanks man.
 
A stock early 340 makes about the same max torque as a stock early 318, and
the biggest tires that you can fit into the Dart tubs are 255s and,
the stock 4bbl-equipped 340 takes off in 2bbl mode,
so
unless you are running a manual trans, I wouldn't waste time pulling the 7.25 out, unless it had a really crappy gear ratio.
But, since I have one, I would install a SureGrip.
 
Unless you want to reweld the spring perches and have to deal with getting the rearend centered, pinion angle, etc. I would just look for an A-body differential housing. The 7.25" will last until you find something as long as you dont beat on it too much. If you do want to weld on spring perches, the 8.25 from an XJ or a ford explorer 8.8 are solid options.
 
dirty white boy said:
junkyards full of mid 90s jeeps with suregrip diffs, and good gear ratios to for cheap!
Click to expand...
This has probably been answered a million times by now but hey, I just joined FABO...
I will be very grateful for some intel on what Jeep differentials will be compatible with the 7 1/4 in my 73 Dart. Or send me to a link. I need to rebuild my 7 1/4 pretty much immediately.
Thanks!

Maybe you can disregard. After thinking about it, I believe the Jeeps are all 8 1/4.
 
Last edited:
Bullethead said:
This has probably been answered a million times by now but hey, I just joined FABO...
I will be very grateful for some intel on what Jeep differentials will be compatible with the 7 1/4 in my 73 Dart. Or send me to a link. I need to rebuild my 7 1/4 pretty much immediately.
Thanks!

Maybe you can disregard. After thinking about it, I believe the Jeeps are all 8 1/4.
Click to expand...
seems like most newer (post acquisition) XJ's are 8.25's; some were dana 30's (similar ring gear size to a 7.25). they use a 1310 ujoint, so if you're shortening your stock driveshaft, you'll need a 1310/7260 conversion joint. they're a skoash over 2" wider than a stock A body 8.25/8.75 drum to drum. met a guy who had a stock '73 340 duster with an A body 8.25 in it, was the original owner. his rear wheels were custom magnum 500's, 15x7 with 3" backspace and 255/60R15's. that means with the XJ rear, stock mopar wheels (+.25" offset, so 4.25" backspace for a 15x7) should center the wheel almost perfectly.
 
Tanman74 said:
I found a decent looking 8 1/4 rear from a '92 Jeep XJ and I'm wondering if it will fit in my '74 dodge dart or what modifications I need to make to it fit.
Car currently has a 7 1/4 since it's a slant car and I'm swapping a mildish 340 in it so I wanted to change the rear end. Specs on the 8 1/4 is that it has 3.55 gears and has been welded.
Click to expand...
Then it better be cheap. As frig. No way would I ever use it. I'd consider it a core to build.
 
Tanman74 said:
Yeeah, I just watched a video of why NOT to weld spider gears lol. I put an wanted ad up in classifieds for a rear that'll bolt on but I'll still stalk marketplace.
Thanks man.
Click to expand...
If you can get it for say no more than 100 bucks. Jump on it. That'll make it worth it to fix it up with new carrier and such. If it's complete with brakes and all it's worth that, although barely.
 
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