Diff gear recommendations

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4spdragtop

4spdragtop

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Hey all, I'm contemplating a diff gear change from our factory 323 to 355.
I'm not looking for top of the line, but want quality and NA made, if possible. Next to zero track time(once for the bucket list)
Mfg recommendations??
Thanks
Steve
 
Doctor Diff- manufacturer seems to depend on the ratio and carrier. Not sure of the country of origin on some of them, some (like the 3.55/741) seem to be his own brand. Could always ask him. Not a bad price, either.
 
4spdragtop said:
Hey all, I'm contemplating a diff gear change from our factory 323 to 355.
I'm not looking for top of the line, but want quality and NA made, if possible. Next to zero track time(once for the bucket list)
Mfg recommendations??
Thanks
Steve
Click to expand...
I don't think a 1/4 of a ratio is gonna make a huge difference in acceleration for the time, effort and $$$. It's like going from 29" tires to 26".
 
273 said:
I don't think a 1/4 of a ratio is gonna make a huge difference in acceleration for the time, effort and $$$. It's like going from 29" tires to 26".
Click to expand...
It's not ALL about acceleration, sometimes it's just about enhancing street manners and drivability- keeping the engine happiest where you do the majority of your driving.
 
Professor Fate said:
It's not ALL about acceleration, sometimes it's just about enhancing street manners and drivability- keeping the engine happiest where you do the majority of your driving.
Click to expand...
True, could be why the OP doing it or maybe not.
 
Professor Fate said:
I assume so- he did say next to zero track time. Maybe once for his bucket list.
Click to expand...
I don't see the point of arguing, if what I said has no relevance for the OP's situation he can just ignore what I said, no biggie, plus you don't need to drag race to want to improve acceleration.
 
About 20 years ago, I bought a complete 489 housing center section with 3.55 gears and Sure Grip from Randy's Ring and Pinion. It was all new parts including the housing. It has performed flawlessly. They are still in business at this website: www.randysworldwide.com
 
My thinking is to increase both gearing and tc modestly?? Am I wrong in thinking this? I'm looking to possibly add some pep without adding BIG gears, and/or BIG TC.
273 said:
I don't think a 1/4 of a ratio is gonna make a huge difference in acceleration for the time, effort and $$$. It's like going from 29" tires to 26".
Click to expand...

Professor Fate said:
It's not ALL about acceleration, sometimes it's just about enhancing street manners and drivability- keeping the engine happiest where you do the majority of your driving.
Click to expand...

273 said:
True, could be why the OP doing it or maybe not.
Click to expand...

Professor Fate said:
I assume so- he did say next to zero track time. Maybe once for his bucket list.
Click to expand...
 
4spdragtop said:
My thinking is to increase both gearing and tc modestly?? Am I wrong in thinking this? I'm looking to possibly add some pep without adding BIG gears, and/or BIG TC.
Click to expand...
The torque convertor will make the biggest difference, the gear change will help a little it's up to you if it worth the $$$ and effort.
 
4spdragtop said:
My thinking is to increase both gearing and tc modestly?? Am I wrong in thinking this? I'm looking to possibly add some pep without adding BIG gears, and/or BIG TC.
Click to expand...
I think you're on the right track- nibble away at it here and there until you're happy with it! Overkill can be your own worst enemy sometimes.
 
Steve, almost with no exception, the Summit Racing private brand of parts is made in USA. So I'd look at Summit gears. I wouldn't be a bit scared of um.
 
Thanks Rob, I see USA Standard and Motive. No Summit brand unfortunately.
I keep forgetting if 741 or 742 is factory for our 67.(I'm at work or I'd chk).
RustyRatRod said:
Steve, almost with no exception, the Summit Racing private brand of parts is made in USA. So I'd look at Summit gears. I wouldn't be a bit scared of um.
Click to expand...
 
4spdragtop said:
Thanks Rob, I see USA Standard and Motive. No Summit brand unfortunately.
I keep forgetting if 741 or 742 is factory for our 67.(I'm at work or I'd chk).
Click to expand...
Which case do you have?
 
Good GRIEF! I cannot believe how much ring and pinion gears have gone up! I got the 4.11 gears for my Ford 9" for 129 bucks. That wasn't terribly long ago.
 
4spdragtop said:
Hey all, I'm contemplating a diff gear change from our factory 323 to 355.
I'm not looking for top of the line, but want quality and NA made, if possible. Next to zero track time(once for the bucket list)
Mfg recommendations??
Thanks
Steve
Click to expand...
I'm happy with my Dr. Diff S-60. The highest gearing available when I bought mine was 3.54 if I remember right. I got 4.10.
4,000 rpm at 70mph sucks, but I don't do a whole lotta freeway driving.
 
273 said:
I don't see the point of arguing, if what I said has no relevance for the OP's situation he can just ignore what I said, no biggie, plus you don't need to drag race to want to improve acceleration.
Click to expand...
sir, this is a wendy's

if we are not here to argue minutiae, then what are we even doing?

273 said:
I don't think a 1/4 of a ratio is gonna make a huge difference in acceleration for the time, effort and $$$. It's like going from 29" tires to 26".
Click to expand...

ohh! now you done did it. just you wait till AJ gets here!
 
I run the 3.55 sure grip. With the 14" tires I feel it is the better compromise between quicker acceleration and freeway speeds (3000RPM at 65mph).
 
Professor Fate said:
Doctor Diff- manufacturer seems to depend on the ratio and carrier. Not sure of the country of origin on some of them, some (like the 3.55/741) seem to be his own brand. Could always ask him. Not a bad price, either.
Click to expand...
I bought a set of 3.55s from Cass 18 months ago and the invoice was marked Motive/Richmond but when they arrived they were in the styrofoam but the outer cardboard box was missing? Hmmm...

I'm breaking them in now, but have no complaints so far. I'm going from 2.76 gears to 3.55 BIG difference.
 
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if you have the 741 case you are limited to 2 available ratios 3.55 and 3.73 there are no aftermarket gear sets made in the North America anymore except those used by OEM ( Ford , GM , Chrysler ) factory builds ,, Motive ( Richmond ) made in Italy but a premium gear set in the orange box , Yukon a premium gear set made in China ,,,, all the others are Chinese / Asian manufactured some good some bad . i prefer to use only Motive gears first ,, then Yukon gear when i build my 8-3/4 differentials now depending on what case is used and gear ratio that is available for that case.
 
And the only way around the limited selection would be to swap the entire pig(which I'm not against), correct?
I saw that Motive was Italian made, so that's a good thing.
I shoulda snagged an empty 83/4 pig at moparfest a couple years back for $50 :BangHead:
john-9 said:
if you have the 741 case you are limited to 2 available ratios 3.55 and 3.73 there are no aftermarket gear sets made in the North America anymore except those used by OEM ( Ford , GM , Chrysler ) factory builds ,, Motive ( Richmond ) made in Italy but a premium gear set in the orange box , Yukon a premium gear set made in China ,,,, all the others are Chinese / Asian manufactured some good some bad . i prefer to use only Motive gears first ,, then Yukon gear when i build my 8-3/4 differentials now depending on what case is used and gear ratio that is available for that case.
Click to expand...
 
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