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323 or 355

3:23 on mine as well with 15" wheels.
2800 RPM @ 70 MPH.
16 MPG on the highway.
 
Ranger 16, ^^^^^^^That's what I'm running in my 65 now.
Pulled the 4.10's and installed 3.23's.
 
Lotta posts quickly. My vote: 3.55 if you’ve got a 4-speed, 3.23 with an auto . Might even do 3.23 with the 4-speed. I’ve had all of them up to 4.88. If you want to accelerate and won’t drive over 60 go deeper but they will suck on the highway.
 
moparnorth said:
what's the matter had a bad day, do not need your lecture crap be patience to new learners you were there once before
Click to expand...
Punctuation isn't very important to you, is it ?
 
moparnorth said:
i thought we are helping each other and give advice
Click to expand...
Here is some advice;
Use a capital letter when starting a sentence.
Use a comma occasionally and end your sentences with a period or a question mark depending on the type of sentence it is.
Here is more:
The gear ratio that you want may not be what others like. Often times it is a matter of compromise. For a cruiser type car where rapid acceleration is not as important as comfortable freeway driving, use a gear that is lower, numerically speaking. 2.76, 2.93 or a 3.23. If you don't care about the engine running 3000 rpms at 70 mph but love snappy acceleration from a dead stop. the deeper gears may be what you want.
Overdrive really helps though. It allows you to use axle gearing to give quick starts ( 3.55, 3.91. 4.10) but then it effectively "tames" those gears into feeling like a 3.23 when in overdrive.
I do NOT suggest using the factory Mopar 833 overdrive 4 speed. It is an okay transmission with a stock 318 but it sucks for use with any performance engine.
 
Nate S said:
Lotta posts quickly. My vote: 3.55 if you’ve got a 4-speed, 3.23 with an auto . Might even do 3.23 with the 4-speed. I’ve had all of them up to 4.88. If you want to accelerate and won’t drive over 60 go deeper but they will suck on the highway.
Click to expand...
thanks
 
Just to reiterate what others have said, my GTX has 275/60-15 rears and 3.55's.
It turns 3000rpm at 65mph, which is borderline uncomfortable for me, especially with the boy racer 3" dual exhaust raising hell....
The car arrived a decade ago with the 3.23's in it factory, but was doggy in town with the 4 speed, so since I was replacing everything back there anyways I went with 3.55's and a fresh SureGrip.
In hindsight, if the car was most always an "around town" car, I'd have gone with 3.91's; if more highway. then 3.23's. The 3.55 is a sort of "close enough but never ideal" ratio compromise.
 
I've mentioned is several previous posts that the driving enviroment where you live can play a part in the gear ratio.
When living in rural Pa, there were mostly back roads, 2 lane and not a straight away to be had.
Now living out west in the desert I can drive for miles and hardly need to turn the steering wheel.
Plus the speed limits are 65 to 80 MPH with in 3 miles from where I live. I have been thinking of 2.76 seriously lately.
 
moparnorth said:
thanks
Click to expand...
Appreciate you sending along thanks to a lot of folks; you can use the 'thank you' icon located at the far bottom right of the post to save ya time on thank you's to your contact.
 
For what it's worth I have a personal comparison/contrast to share based on actual driving, with my actual cars. I am fortunate to own 2 GTX's, both with their original stock factory drive lines.

GTX #1, is Baby Blue, a '68 automatic, with a 3.23, bone stock 440, except for a Holley Street Avenger carb, electric fuel pump, and electronic ignition. She was a family car for 15 years before I bought her in 1983. No shortage of low end torque with this set up. Car ran consistent 14.2s at Capitol Raceway with the original AVS carb back in the day. Comfortable highway cruiser with G70x14 Firestone red line radials.

GTX #2 is a '69 factory A33 Track Pak, numbers matching. Driven by a juvenile delinquent type street racer back in the '70s, then 22 years of hibernation. When I bought her five years ago she had 275-60-15's in the back, and her original 3:54 Dana, and 833 4-speed. Original Carter AVS still in place, factory intake. Cam at the time was a .284/.284 purple shaft, since replaced with a Comp Thumper. Drove the car 1300 miles from Waterloo, Iowa to State College, PA. Not a pleasant highway cruiser IMO, but a blast to drive around town. A local Mopar speed shop suggested the Comp cam to get more torque with the factory 1st gear, and I'm really happy with the result. Also running 235-60-15's front and back now, personal preference for the car sitting stock height.

Sometimes I'm in the mood for the smooth highway cruiser, sometimes the more raucous 4-speed. Not saying either combination is better or worse, and as others have stated, the 3:23/3:55 equation can be shifted by shuffling other components.
 
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Ok, I'll add my 2cents.
As to overdrive
If only 25% of your driving is gonna be hiway, then I would put overdrive on the backburner, especially the A833od. And here's why;
The Mainshaft gear in that box has, IIRC 21 teeth. At any one time, I doubt there are more than 2 teeth transmitting power. At 1800rpm, and cruising,with a 318 this is fine. but
With anything bigger than a 318, or even with a 4bbl 318, if you shift into that gear with anything more than nearly closed throttle, ZING goes the engine into the rev-limiter, all the teeth having shattered off the M/S gear. I tore three apart, before I abandoned those.

As to the A833/ direct fourth;
This brute can take anything your streeter can dish out.

As to 275/60-15s, at 28tall, this is a great straightline tiresize, and sets the stage for what comes after.

I take it that you have neither a trans nor a rear end yet. And that you are just discussing possibilities. To that end, being 75% a city car, you can run any dang 3-series rear gear you want to. But the best one will depend on what you want to do with your car. I'm gonna talk about performance cuz everybody else got you covered for cruising. And there were some excellent posts.
So then, to my way of thinking, the best rear gear ratio is the one that wants to marry your camshaft.
What I mean is; the bigger your cam is, the higher will be the power-peak. And the higher the power peak is, the higher will be the torque peak. And the higher the torque-peak is, the more careful you will have to be about the engine-build so that the bottom-end won't turn into a marshmallow.
So then, here's the thing, as a streeter, you have a two-gear car. Usually,at WOT, first gear spins right thru, and then you will hit 60/65 mph somewhere in second gear. So if you have a big cam, and if you want to be quick, you will need a big rear gear, to use all that power you engine is making. There is zero sense in having a 6000 rpm engine, that doesn't even hit 5000 by 60mph. Your big power engine will smoke thru first gear to say 50mph, and then choke at 4800@60, never having got even close to the power-peak. You follow me?
Here's an example;
Say you built a hot street strip car with a cam that peaks around 5800, and shifts at 6100, and you put those 3.55s on her, Ok then, 60mph will be 4900 in second. Whatever power this monster makes at 5800 DOES NOT MATTER, because you never got there! Also, whatever power this monster makes at 4900, your better choice would be to have a 4900rpm power-peak. This usually has the bonus of having MORE POWER BELOW about 3500rpm. With a manual trans streeter, that low-rpm from idle to 3500 is gonna become very very important, because about, IDK 95% of the engine's life, is gonna be spent in that zone.
So, if you paid attention, in this scenario, the 3.55 rear gear dictated where the power peak should be ....... for best trap-speed at 60mph, and usually, this will result in a low-ET.
If you are not interested in this kindof thing then say so.
If you are interested in low-ET at another speed, then your choices will be different.

Next I want to talk about 30/35 mph. Cruising at 32 with 3.55s and those 28" tires will get you 1900 in third, 2600 in second, and 3600 in first. So say you are just tooling along in third@1900, which is very comfortable. The engine is getting reasonably efficient, and is telling you that by the song the pipes are singing. But the mood strikes you to accelerate briskly, and so you downshift into second,the Rs pop up to 2600, and if you have a hi-compression 360, she busts the tires loose, and pow! you are gone. But say you have just an 8/1 318LA; no problem, down into first gets you warp-drive at 3600.
This is why I run 3.55s, there's always a gear at 32 mph for every need.
And with 28s, the bonus is 65=2770; a tad high for some guys, but for 20 minutes I can handle it.

Next I want to talk about idle to 3500 with a manual trans.
First, parading;
If your big cam engine cannot be tuned to run less than 700rpm in first gear; that is 6.2mph, your slowest driving speed. That's gonna suck. Well for me it did. Mostly cuz nobody can walk that fast for long, so parading is O-U-T. To parade, you gotta get down to ~3.5 mph, maybe 4.0 at the best. There is no 3-series gear that will go there with a 2.66low and 28s. Even 3.91s can only get you 4.0@500rpm. How do you cam for that? Well I guess the factory 318 cam will go there..... But good news, the Commando A833 has a low of 3.09, and 4.0mph becomes, wait for it ....... 580rpm, that is doable. Not easy, not cheap, but doable, with up to a 230* HFT cam. Better with a 223* HFT cam.
next; drive-away;
Every time you take off, you gotta slip the clutch, and give her some rpm. The smaller your rear gear, the longer the time of the slipping needs to be. And the softer the bottom-end is, the higher you will have to rev it to get moving briskly.
With an 8/1 318LA, and 3.55s, with those 28s, It's almost embarrassing.
I like a dump-it-and-go deal. Give her a lil blip, to bring the flywheel on line, them wham the clutch out most of the way, simultaneously feeding it gas, for the last lil bit. THEN giving it gas. That's how I like it. That takes several tricks, the three biggies being ; tons of low-rpm torque, a heavy flywheel, and a big starter-gear. Think grain-truck,loaded, on soft black dirt. Of these three, you can move one of them up or down, if the other are adequate enough.
Say you had a 360 with tons of torque, then you could sacrifice flywheel, for rear gear. If you had a Low-C 318LA then you would need BOTH heavy flywheel and BIG starter gear. I tell ya, you haven't lived until you let the clutch out with 5.38s.
Next, torque;
If you don't got much, you will never have fun. 3500 is 31mph with a 2.66low and 3.55s. You are gonna be in this zone for most of your engine's life. If your engine is sucked out in this zone, you are gonna be one unhappy guy. It's not like the automatic trans guys who stick a 2800stall, or a 3200 stall in the trans, and that combo always has bite. No, with a manual trans, you have no help from the TC. Your engine has got to have pure spunk. 8/1 318LAs need not apply. This takes cylinder pressure. Which is a combination of Cubic inches,Sca or Compression Ratio, and ICA or when the intake valve closes. Simple right.

So now you know how stuff work, you just have to build the engine to make the best use of the chosen gears.

If the engine is already built ........... then that could be a tougher match.
But here's something to consider; with a bigger engine, in the zero to 60 contest, you're only looking at, I'm guessing, maybe a half a second between the worst 3 series match and the best. So if you have a 400 hp combo,, who cares it, it is gonna spin the tires to 80mph anyway.
But with a low-compression 200hp 318LA, now it gets to be pretty important.

And here is the Formula you need;

mph= (rpm x TC)/ 1056 x R1 x R2
Where TC is the Tire Circumference, and the Rs are your gearing. The 1056 is a conversion factor for distance and time.
the std. A833 ratios are 2.66-1.92-1.40-1.00
The MP 3-series gears are, 3.23/3.55/3.73/3.91
Maybe more than 2 cents worth, but after the tuff intro you got, I'm just trying to;
Jus trying to help.
 
Last edited:
AJ/FormS said:
Ok, I'll add my 2cents.
As to overdrive
If only 25% of your driving is gonna be hiway, then I would put overdrive on the backburner, especially the A833od. And here's why;
The Mainshaft gear in that box has, IIRC 21 teeth. At any one time, I doubt there are more than 2 teeth transmitting power. At 1800rpm, and cruising,with a 318 this is fine. but
With anything bigger than a 318, or even with a 4bbl 318, if you shift into that gear with anything more than nearly closed throttle, ZING goes the engine into the rev-limiter, all the teeth having shattered off the M/S gear. I tore three apart, before I abandoned those.

As to the A833/ direct fourth;
This brute can take anything your streeter can dish out.

As to 275/60-15s, at 28tall, this is a great straightline tiresize, and sets the stage for what comes after.

I take it that you have neither a trans nor a rear end yet. And that you are just discussing possibilities. To that end, being 75% a city car, you can run any dang 3-series rear gear you want to. But the best one will depend on what you want to do with your car. I'm gonna talk about performance cuz everybody else got you covered for cruising. And there were some excellent posts.
So then, to my way of thinking, the best rear gear ratio is the one that wants to marry your camshaft.
What I mean is; the bigger your cam is, the higher will be the power-peak. And the higher the power peak is, the higher will be the torque peak. And the higher the torque-peak is, the more careful you will have to be about the engine-build so that the bottom-end won't turn into a marshmallow.
So then, here's the thing, as a streeter, you have a two-gear car. Usually,at WOT, first gear spins right thru, and then you will hit 60/65 mph somewhere in second gear. So if you have a big cam, and if you want to be quick, you will need a big rear gear, to use all that power you engine is making. There is zero sense in having a 6000 rpm engine, that doesn't even hit 5000 by 60mph. Your big power engine will smoke thru first gear to say 50mph, and then choke at 4800@60, never having got even close to the power-peak. You follow me?
Here's an example;
Say you built a hot street strip car with a cam that peaks around 5800, and shifts at 6100, and you put those 3.55s on her, Ok then, 60mph will be 4900 in second. Whatever power this monster makes at 5800 DOES NOT MATTER, because you never got there! Also, whatever power this monster makes at 4900, your better choice would be to have a 4900rpm power-peak. This usually has the bonus of having MORE POWER BELOW about 3500rpm. With a manual trans streeter, that low-rpm from idle to 3500 is gonna become very very important, because about, IDK 95% of the engine's life, is gonna be spent in that zone.
So, if you paid attention, in this scenario, the 3.55 rear gear dictated where the power peak should be ....... for best trap-speed at 60mph, and usually, this will result in a low-ET.
If you are not interested in this kindof thing then say so.
If you are interested in low-ET at another speed, then your choices will be different.

Next I want to talk about 30/35 mph. Cruising at 32 with 3.55s and those 28" tires will get you 1900 in third, 2600 in second, and 3600 in first. So say you are just tooling along in third@1900, which is very comfortable. The engine is getting reasonably efficient, and is telling you that by the song the pipes are singing. But the mood strikes you to accelerate briskly, and so you downshift into second,the Rs pop up to 2600, and if you have a hi-compression 360, she busts the tires loose, and pow! you are gone. But say you have just an 8/1 318LA; no problem, down into first gets you warp-drive at 3600.
This is why I run 3.55s, there's always a gear at 32 mph for every need.
And with 28s, the bonus is 65=2770; a tad high for some guys, but for 20 minutes I can handle it.

Next I want to talk about idle to 3500 with a manual trans.
First, parading;
If your big cam engine cannot be tuned to run less than 700rpm in first gear; that is 6.2mph, your slowest driving speed. That's gonna suck. Well for me it did. Mostly cuz nobody can walk that fast for long, so parading is O-U-T. To parade, you gotta get down to ~3.5 mph, maybe 4.0 at the best. There is no 3-series gear that will go there with a 2.66low and 28s. Even 3.91s can only get you 4.0@500rpm. How do you cam for that? Well I guess the factory 318 cam will go there..... But good news, the Commando A833 has a low of 3.09, and 4.0mph becomes, wait for it ....... 580rpm, that is doable. Not easy, not cheap, but doable, with up to a 230* HFT cam. Better with a 223* HFT cam.
next; drive-away;
Every time you take off, you gotta slip the clutch, and give her some rpm. The smaller your rear gear, the longer the time of the slipping needs to be. And the softer the bottom-end is, the higher you will have to rev it to get moving briskly.
With an 8/1 318LA, and 3.55s, with those 28s, It's almost embarrassing.
I like a dump-it-and-go deal. Give her a lil blip, to bring the flywheel on line, them wham the clutch out most of the way, simultaneously feeding it gas, for the last lil bit. THEN giving it gas. That's how I like it. That takes several tricks, the three biggies being ; tons of low-rpm torque, a heavy flywheel, and a big starter-gear. Think grain-truck,loaded, on soft black dirt. Of these three, you can move one of them up or down, if the other are adequate enough.
Say you had a 360 with tons of torque, then you could sacrifice flywheel, for rear gear. If you had a Low-C 318LA then you would need BOTH heavy flywheel and BIG starter gear. I tell ya, you haven't lived until you let the clutch out with 5.38s.
Next, torque;
If you don't got much, you will never have fun. 3500 is 31mph with a 2.66low and 3.55s. You are gonna be in this zone for most of your engine's life. If your engine is sucked out in this zone, you are gonna be one unhappy guy. It's not like the automatic trans guys who stick a 2800stall, or a 3200 stall in the trans, and that combo always has bite. No, with a manual trans, you have no help from the TC. Your engine has got to have pure spunk. 8/1 318LAs need not apply. This takes cylinder pressure. Which is a combination of Cubic inches,Sca or Compression Ratio, and ICA or when the intake valve closes. Simple right.

So now you know how stuff work, you just have to build the engine to make the best use of the chosen gears.

If the engine is already built ........... then that could be a tougher match.
But here's something to consider; with a bigger engine, in the zero to 60 contest, you're only looking at, I'm guessing, maybe a half a second between the worst 3 series match and the best. So if you have a 400 hp combo,, who cares it, it is gonna spin the tires to 80mph anyway.
But with a low-compression 200hp 318LA, now it gets to be pretty important.

And here is the Formula you need;

mph= (rpm x TC)/ 1056 x R1 x R2
Where TC is the Tire Circumference, and the Rs are your gearing. The 1056 is a conversion factor for distance and time.
the std. A833 ratios are 2.66-1.92-1.40-1.00
The MP 3-series gears are, 3.23/3.55/3.73/3.91
Maybe more than 2 cents worth, but after the tuff intro you got, I'm just trying to;
Jus trying to help.
Click to expand...
I will be running a 383 HP stock a833, should I get the 18 or 23 spline. Also thank you for your lengthy info. It will take a while for me to take in. Greg
 
Last edited:
Want to build your own combo for Best of both worlds ?, Then if anyone is interested I have for sale very rare 833 low mileage complete extra wide ratio gear set with low 3.09 1st gear and 4th is non OD 1:1 all gears cluster and synchro teeth are as good as new, and to complete the perfect cruiser combo my complete 8 3/4 2.94 ratio rear . Best of both worlds. I am located in south western ON , thx Doug, [email protected]
 
SCHU said:
Want to build your own combo for Best of both worlds ?, Then if anyone is interested I have for sale very rare 833 low mileage complete extra wide ratio gear set with low 3.09 1st gear and 4th is non OD 1:1 all gears cluster and synchro teeth are as good as new, and to complete the perfect cruiser combo my complete 8 3/4 2.94 ratio rear . Best of both worlds. I am located in south western ON , thx Doug, [email protected]
Click to expand...
sorry my mechanic has one for me to install
 
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