3.31 or 3.55

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wireweld

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I need your input on the better of the two gears that I have. 3.31 or 3.55?
The engine was dynoed at 595hp@6100 and 550tq@4600. The car is a 72 dart weighin in at 3800 lbs. 904 with the low gear set, 9.5 dynamic 3200 stall and a gear vendors.
This car is a street car 95% of the time and when I go to the strip I can put in either 3.91 or 4.56 gears. I am looking to see which gear would be better for the street and not kill the performance of the engine. Or is there little difference between the 2.
 
Pretty much anyone will tell you that a 3.55 gearset is the best all around.

I am running a 3.23 gear set and it is very fun and very fast and super on the highways but a set of 3.55's will definitely be more spunky off the line, and will compromise a bit on the highway, but right now I usually have to cruise the streets hight revving in third gear because fourth just drops me too low.

I have talked to many Mopar guys who have played with different gear sets and they all steer me to the 3.55 for the best all around fun.

I have a 30" tall rear tire so a set of 3.73's would not be too radical.
 
I'd run a 3.73 on the street and strip... 3.73 is right in the middle for me, not to high and not to low.
 
wireweld said:
I need your input on the better of the two gears that I have. 3.31 or 3.55?
The engine was dynoed at 595hp@6100 and 550tq@4600. The car is a 72 dart weighin in at 3800 lbs. 904 with the low gear set, 9.5 dynamic 3200 stall and a gear vendors.
This car is a street car 95% of the time and when I go to the strip I can put in either 3.91 or 4.56 gears. I am looking to see which gear would be better for the street and not kill the performance of the engine. Or is there little difference between the 2.
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3800 pounds?? holy crap thats a heavy *** dart...lol..


what gears did ya tell them you were using when you ordered the converter? it can make a huge difference.

with 550tq the 3.21 should be fine on the street as long as the converter isn't too loose...

it also depends on what street use means to you. to me it means going on 2+ hour drives in the highway at 80+ mph. and 3.55 suck for that. been there done that.... but if your just putting around town a 3.55 will be fine...


i'm running a 2.94 and love it. actually want od NOW.. :)
 
3800 pounds, my wagon with me in it weighs that much!!

I would go with 3.55's but I have an 833od.

CleanVolare.jpg
 
Wow my bblk dart only weighs 3280 with me in it [71] either gear would be fine, the 3.31's prob a little more practical with tire size, I will be running 3.73's with 27.5 tall street tire
 
My 3:55's put me at about 3000 rpm at 60 mph with a 25 inch tire and a 4 speed. Don't have much use for 4th gear in the city as was previously stated. I had 3:23 open diff previously and she still pulled nice and strong once the tire stopped spinning. I would like to try a 3:23 sure grip.
 
i would use atleast a 3.73, and use the GV in 2nd over at the track...

Or i would use a 3.90.

You might have wanted to try Martin Saines TC's he has a nice tc that will give you the rpm you're looking for to launch and then lock up like a clutch...
 
I not sure why my car weighs so much but thats what the scale said.
I am also using a CRT reverse manual vb. With the gear vendors, I am starting to think that 3.55 would give good cruising along with good launch. Does that sound about right?
 
Considering you say you have an extra 3rd member for racing and with that much power and 27" tires if you are really serious about wanting good cruising spirits go with the 3.31's. I have 3.55's in my car with 28" tires and it runs 2800 at 60 mph so yours with the shorter tire would be nearly identical. Just right for cruising IMO.
 
Oh yeah, I think I'd find a different scale if I were you. I thought my 68 Cuda fastback was a pig at 3640 with me in it but man a Dart that weighs 3800 lbs!! Unreal!! That's big block B-body territory.
 
If you dont run the 3.55s can I buy them from you?
 
I have 27" diameter tires on my Dart. It had a 3.23 Sure Grip. I thought it was too tame for the Street, where it lives mostly.

Got a 3.91 - Great for fun on the Street, not so great on the Freeways...


I think that a 3.55 would be perfect as an all around gear.


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He has a GV...... you would be making a HUGE mistake playing with a gear like that and giving that up.

I have a 26" tire, 3.73 and at 75mph im at 2600......with the GV...

I would use the 3.90 you could even go 4.10 with the GV..
 
Supershafts said:
He has a GV...... you would be making a HUGE mistake playing with a gear like that and giving that up.

I have a 26" tire, 3.73 and at 75mph im at 2600......with the GV...

I would use the 3.90 you could even go 4.10 with the GV..
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I agree, I don't think the people that replied noticed he has a Gear Vendors was on it.

Running a 27" tire, gear vendors (0.78 OD), and a 3200 stall with 3.21 gears might be tough on the converter if you cruise in overdrive. Might even lug a high HP motor like he has. The car would be a 2050 RPM at 65 mph!

Gear ratio/mph calculator: http://vexer.com/automotive-tools/speed-rpm-calculator
 
I agree, I don't think the people that replied noticed he has a Gear Vendors was on it.
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your right. i didn't see it in the first post because its off the side of the screen....
 
Would using the 3.55 be acceptable?
I saw tonite that at 70, I was running about 2800 rpm. This is with the 3.91's.
 
I have used both the 3.23 and currently the 3.55 sure grip. I would say there is not a HUGe difference in the two, but I find the 3.55s definitely give me a little more quick response off the line and get up and go. They are also nice on the highway if you need that road to travel as well.
 
abodyjoe said:
your right. i didn't see it in the first post because its off the side of the screen....
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Me either

wireweld said:
Would using the 3.55 be acceptable?
I saw tonite that at 70, I was running about 2800 rpm. This is with the 3.91's.
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I never noticed you have a gear vendors. If your running 2800 at 70 I'd leave it be. Your converter may slip and heat up if you go any taller on the gear.
 
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