Looking for some Differential advice

Brooks James

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some better gears would certainly help your slant, but you might want to say what you are going to do with the car. 3.73s are pretty low if you get out on the highway at all. You'll find yourself running out of 3rd gear and winding up that slant at 70 mph. I'd pick 3.23s for a run around drive it anywhere car.
Save it money, go to a rpm/tire size, final drive ratio calculator, cut rpm down with taller tires
 

33IMP

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No. I haven’t taken it apart. I’ve been working on it from the top down. I’m finally done with the interior and wiring
Lots of vids on you tube how to check without pulling the cover. I sure wouldn't pull the cover just for curiosity. Just a little harder to do with an open rear, but if you've got a floor jack, you could check in about ten minutes
 

72DartGuy

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Lots of vids on you tube how to check without pulling the cover. I sure wouldn't pull the cover just for curiosity. Just a little harder to do with an open rear, but if you've got a floor jack, you could check in about ten minutes
I don’t have a floor jack. I know just enough to be dangerous, lol
 

RustyRatRod

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I was told that with a 408 motor and built 727 trans my 7 1/4 rear end would not last a week
You can make it last as long as you need to with a conservative right foot.
 

MidnightSwinger

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3.23 vs 3.73 @65mph with your chosen rear tire size.

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AJ/FormS

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Save it money, go to a rpm/tire size, final drive ratio calculator, cut rpm down with taller tires
That's a great idea, but from the maximum that will fit, to the smallest anyone is likely to install, is only about the equivalent of One gear size;
from 2.76 to 2.94 is about 6.1%, and from 2.94 to 3.23 is about 9%
The tallest tire that the 72 Dart will accept is about 28 (maybe), but to install it, the axle may need to be moved back. So let's say a 27, cuz I don't think there is anything between 28 and 27. The shortest tire that one might install would likely be a 24.5 .
from 24.5 to 27 is about 9%. But 24.5 will be useless against a 408stroker.
So while the idea is a good one, it sorta depends on from where you are starting.
I've had a few Darts of those years, and I sorta recall installing some 225/75-15s, which, by the math is 28.3. But they have to be well inside the tubs to not rub on the rockers.
 
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Killer6

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3.73's aren't going to fix the fact that there's something wrong with that Slanty, a 2bbl on an Offy intake that struggles to do the double nickle? My '69 Dart Custom HT would do a top-end of close to 100mph, 2 passengers & Myself, about 490# payload on "Hunter stretch" which is an up-hill grade on the return trip. That's 2.76's & a bone stock 1bbl car with a Cherry Bomb, stock 13" tires replaced with 205/75-14's. Unless You're in the hills with some steep grades, I think the fuel supply or timing etc. needs some attention.
 
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72DartGuy

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3.73's aren't going to fix the fact that there's something wrong with that Slanty, a 2bbl on an Offy intake that struggles to do the double nickle? My '69 Dart Custom HT would do a top-end of close to 100mph, 2 passengers & Myself, about 490# payload on "Hunter stretch" which is an up-hill grade on the return trip. That's 2.76's & a bone stock 1bbl car with a Cerry Bomb, stock 13" tires replaced with 205/75-14's. Unless You're in the hills with some steep grades, I think the fuel supply or timing etc. needs some attention.
Thanks!
 

72DartGuy

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12many

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Amazon sometimes has good pricing on ring and pinion sets. Yukon, Richmond etc. Gotta scroll through the results, try different search words to get best results:

 

12many

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That Barnett performance price for the Yukon is excellent, considering that summit wants $150 more.
Granted, Summit likely has it in stock whereas it gets drop shipped from Barnett, but I’ve gotten other stuff drop shipped within a week or so. I’ve dealt with them quite a bit. Ive found some outstanding pricing on stuff from there, especially Howard’s Cams product. Some in stock, others drop shipped. It’s a smaller operation, a little old school in a good way
 

dirty white boy

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I’ve got 205-70-14’s on the front and 265-60-14’s on the rear. Not changing them. I have an offenheiser? Intake and a 2bbl Holley now. It’s a dog. It’ll do maybe 50 on the freeway going up hill. When I downshift it just bogs out. I have a 408 Stroker and a built 727 to run that rear end with. I just don’t want my car to sit for another year.
somethings off on your tune up!! wheres your initial and tottle timing at?? maybe carb needs tweeking to,..when last time valves been adjusted?
 

72DartGuy

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Yeah, I agree my tune is out. I found a guy here who knows slants. I’m taking her in tomorrow to have him test drive it. Needing a tuneup makes a lot of sense. Thanks!
 
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