best gears in rear with 4 spd?

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dustya_383

dustya_383

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Wat are the best gears to run with a 4speed?? I have 323s now? Wat are u guys running,want it to get up quick but also don't want it at 4500 when cruising
 
You got the gears now, you could step up to 3.55 if you wanted for a better hole shot
 
dustya_383 said:
Wat are the best gears to run with a 4speed?? I have 323s now? Wat are u guys running,want it to get up quick but also don't want it at 4500 when cruising
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Well gee...................

You've posted a question nobody can answer. We don't know WHAT you want for RPM, and we don't know what RPM you run now "when cruising" nor do we know "what cruising" MEANS

Here's the deal:

ALL traditional 4 speeds, 3 speeds, and Torqueflites are 1:1 in high gear, which means that "cruising" RPM is determined by

rear gear ratio and tire size.

YOU have to determine what "cruising" means to YOU. 45? 65? 70? 140?

There are plenty of online calculators

[ame="http://www.google.com/search?hl=en&source=hp&biw=1366&bih=637&q=mph%2C+rpm%2C+calculator&aq=f&aqi=g1g-b4&aql=&oq="]mph, rpm, calculator - Google Search[/ame]

So take your tire size, the rear ratio you have now, and decide what mph you want to call "cruise" and calculate it, then decide how much HIGHER RPM you can "handle" and plug that into the formula. That will tell you what gear you think you want.
 
also what year 4 speed box ?? there are 3 different 1st gear ratios,, exaample i have a 1965 box out of a formula S it has a 3.09
1st gear ratio, which helps me out of the hole or to get rolling quicker fro ma dead stop,,,meening i need less in the rear end for lower cruising RPM,S
 
67Dart273 said:
Well gee...................

You've posted a question nobody can answer. We don't know WHAT you want for RPM, and we don't know what RPM you run now "when cruising" nor do we know "what cruising" MEANS

Here's the deal:

ALL traditional 4 speeds, 3 speeds, and Torqueflites are 1:1 in high gear, which means that "cruising" RPM is determined by

rear gear ratio and tire size.

YOU have to determine what "cruising" means to YOU. 45? 65? 70? 140?

There are plenty of online calculators

mph, rpm, calculator - Google Search

So take your tire size, the rear ratio you have now, and decide what mph you want to call "cruise" and calculate it, then decide how much HIGHER RPM you can "handle" and plug that into the formula. That will tell you what gear you think you want.
Click to expand...


well my definition of cruising is like 70 or 80. i plan on changing from a 275 60 15 to a 275 45 18 or 295 50 15 i believe a 18inch wheel with a 45 series tire is 26 or 27 inches , was told by my machinist 3:91 would be good. ill play with the calculator see whats the best
 
dustya_383 said:
well my definition of cruising is like 70 or 80. i plan on changing from a 275 60 15 to a 275 45 18 or 295 50 15 i believe a 18inch wheel with a 45 series tire is 26 or 27 inches , was told by my machinist 3:91 would be good. ill play with the calculator see whats the best
Click to expand...


Are you going to do much cruising at 75-80 with a 27" tire and 3.91 gears? Unless you have OD of some kind its going to suck. Been there done that. An occasional blast isn't bad to those speeds but if you plan on doing a bunch of cruising go with a 3.23 or 2.94 if not running OD.
 
Once again, I agree with Joe. 391s are too tall a gear to run that short of a tire for any distance on the highway.

Decide what size tire you want to run, then plug it in to the calculator. It will tell you your cruising RPM at different MPHs. This is the calculator I used cause it is set up with Mopar ratios and is more visual (read fun!!).

speed/rpm calculator

I went with a 28 inch tire and 3.55 gears. Should cruise 70 at about 3 grand.
 
i run alot of highway around here. at 70 mph, i run at 3500 rpm. with 26 inch tires. i am thinking about swapping the 3:55 out for either 3:23 or 2:9? here very shortly, as i do not run on the track with the car
 
I just bought a set of 3:73 gears and im going to be running a 27" tire. Had 3:91 but after sitting 36 years the ring gear got rusty and pitted really bad.
 
You already have the 3.23 run them, you will be happy.

My 71 challenger that I drove alot I used 3.23 most of the time, the 3.91 I had were just to low for the highway.

The current duster I am building I am using a 3.23 with a straight 4-speed.
I also have a 4.30 gear to run with the OD 4-speed.
No matter which combination I use I will still end up with a 3.23 final ratio.

Anything more than a 3.55 on the street you will be miserable.
 
abodyjoe said:
Are you going to do much cruising at 75-80 with a 27" tire and 3.91 gears? Unless you have OD of some kind its going to suck. Been there done that. An occasional blast isn't bad to those speeds but if you plan on doing a bunch of cruising go with a 3.23 or 2.94 if not running OD.
Click to expand...


Abso freekin lootely
 
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