Diff gear recommendations

[4spdragtop]

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

 

[Professor Fate]

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.

 

[273]

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

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".

 

[Professor Fate]

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".

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.

 

[273]

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.

True, could be why the OP doing it or maybe not.

 

[Professor Fate]

True, could be why the OP doing it or maybe not.

I assume so- he did say next to zero track time. Maybe once for his bucket list.

 

[273]

I assume so- he did say next to zero track time. Maybe once for his bucket list.

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.

 

[harrisonm]

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

 

[4spdragtop]

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.

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".

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.

True, could be why the OP doing it or maybe not.

I assume so- he did say next to zero track time. Maybe once for his bucket list.

 

[273]

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.

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.

 

[Professor Fate]

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.

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.

 

[RustyRatRod]

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.

 

[4spdragtop]

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).

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.

 

[RustyRatRod]

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).

Which case do you have?

 

[RustyRatRod]

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]

Dunno lol. I'll climb under after work.

Which case do you have?

 

[Ottmundr]

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

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.

 

[4spdragtop]

Looks like 741, I'm a dumbass.

 

[junkyardhero]

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.

sir, this is a wendy's

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

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".

ohh! now you done did it. just you wait till AJ gets here!

 

[Murray]

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).

 

[4spdragtop]

Thanks Murray, I'm running 15" tires, do you know what TC you're running?

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).

 

[BrianT]

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.

I can confirm this. I bought a set of 3.55 gears from him about a year ago and he shipped them with the inside styrofoam but not the outside box? Almost like he didn't want me to know what brand they were?

I'm breaking them in now, but have no complaints so far. I'm going from 2.76 gears to 3.55 BIG difference.

 

[john-9]

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.

 

[A56]

Looks like 741, I'm a dumbass.

Yeah, I believe all 2nd gen Barracudas were 741s. My '69 340 is.

 

[4spdragtop]

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

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.