Opinions wanted on 3.78 in a Columbia
 

Right now I have 3.54 gears in my '36 5 window. A friend has a '36 3 window with a 4.11 and a Columbia. We drove both cars just a few minutes apart. I run about 3000 rpm at 60 mph. His car did not have a tach but the engine speed sounded about the same at 60 mph.


Mine just sounds like it needs another gear at road speed. Around town I am fine with the stock 3-speed. Would the 3.78 be a good intermediate selection for interstate travel?

Re: Opinions wanted on 3.78 in a Columbia
 

Not sure what you are asking but going from a 3.54 to 3.78 would be the opposite of what you want. I think 3.78 and a od columbia would be perfect.


I have a 3.78 with a 36% mitchell od on the truck. Rebuilt engine. Runs swell at 60-70 at around 2-2.500 (Im ear guessing as I don't have a tac. it's not winding out anyway) Plenty of rpm left if the engine hp could pull it to go more.

Re: Opinions wanted on 3.78 in a Columbia
 

Sorry, yes forgot to mention that I am asking about installing a 3.78 in a Columbia for improved highway driving.

Re: Opinions wanted on 3.78 in a Columbia
 

I probably misunderstood. I think that's a winning combo. Smarter folks will add, but that's not a bad plan.


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Re: Opinions wanted on 3.78 in a Columbia
 

This is still a bit confusing, I am a fan of lower gearing because of the improved acceleration and especially with an OD. But most people that refer to ḧighway driving are looking for higher gearing. I would think the a 3.54 would be about as high as you would want to go, but it would be possible to go a little higher. For all around driving I would opt for a 3.78 or even a 4.11, but then again, that is not what is normally referred to as highway gearing.

Re: Opinions wanted on 3.78 in a Columbia
 

JSeery, he's asking about putting a OD in. OD's are pretty nice for the highway getting rpms down for long distance. Only have to engage once you are doing 60-70 at higher rpms.


What I get from it.

Re: Opinions wanted on 3.78 in a Columbia
 

I see! Then a 3.78 with an OD added would be a great combo IMO, LOL :)

Asleep at the wheel (keyboard) again! Guess the title was throwing me.

Re: Opinions wanted on 3.78 in a Columbia
 

Thanks everyone, yes Tinker has expressed my poorly explained desires, just trying to get more highway speed combining the 3.78 with a Columbia.

Re: Opinions wanted on 3.78 in a Columbia
 

Ya probably my bad too for not reading the title as much as I did with the context within. hahahaha :eek::D but i digress..

Re: Opinions wanted on 3.78 in a Columbia
 

I have a Columbia in my 40 with 3:78 gears . Bone stock 221 flathead and it works fine.

Re: Opinions wanted on 3.78 in a Columbia
 

What kind of highway speeds are you comfortable at? 65-70?

Re: Opinions wanted on 3.78 in a Columbia
 

No one mentioned the shifted ratio of the Columbia
A 3:78 Columbia shifts to 2:78
A 4:11 Columbia shifts to 2:97
Either one gives a good Highway final rear gear when shifted.
The engine/trans combo and how you use the car without engaging the Columbia is the question.
Right now we have two cars with Columbia overdrives, one is using a mildly hopped up 21 stud V8 using the 4:11/2:97 combo.
The other is using a 55 Dodge Hemi, mildly hopped up, using the 3:78/2:73 combo.
Both cars have 1:1 final drive in the transmissions.
They are both currently under construction, I'll know more in the Spring.

Re: Opinions wanted on 3.78 in a Columbia
 

I'm curious how these run for you, 32phil. I'll have 3.78's in my '28 AV8. It's a rumble car and that space will be used for my boys.

I want a Columbia and will add one to the car someday.

Re: Opinions wanted on 3.78 in a Columbia
 

I have always preferred the 3:78 with or without an overdrive. In the Midwest we have a lot of hills - some steep. The 3:78 provides good "traction" when pulling away from a dead stop and will also allow the engine comfort at cruising speeds.

Many guys ask: "Can the car comfortably do 65 - 70 MPH with a Columbia and a 3:78?" A: Sure it can.
I ask: "Do you have a stock suspension and brakes?"
"If so, are you ready to stop as quickly as may be necessary at those speeds?"
"Can you quickly maneuver out of the way of the idiot in the BMW that just swerved directly in to your lane"?

Re: Opinions wanted on 3.78 in a Columbia
 

Kube,
I am currently working on converting to hydraulics, but that is a different thread.


The rest of the suspension will be stock. I am also working on converting from the '36 steering to '37 steering. I do have all of those parts, just no time.


I do have a friend here in Denver that does build Columbias and I do already have the right side housing, but again, time and money.


Thanks
Steve

Re: Opinions wanted on 3.78 in a Columbia
 

I have a stock 39 flat motor with a T170 4 speed and a Columbia with 3.78 R&P. I've been up to 80mph with more to go but the bias plys were doing their wiggle dance and I didn't want to end up in the ditch. Lincoln brakes up front with 39 juice in the back. I did the conversion after some freeway driving with the stock 4.11 and 3 speed crashbox. I found it to be scary trying to keep up with modern traffic, with the motor revving so high. MUCH better now. Looking forward to some Diamondbacks in the future.
Considering some discs for the front, but not before new tires.

Re: Opinions wanted on 3.78 in a Columbia
 

Thanks JohnDee. I will look into some 3.78s when I can afford them. I do see a set on ebay right now but not ready to spring for them.

Re: Opinions wanted on 3.78 in a Columbia
 

I don't understand the 3000 rpm at 60 mph with a 3.54 rear gear. If you have stock tires around 28" tall, the rpm should be more like 2550, and about 2722 with a 3.78. A 4.11 calculates to 2959 rpm at 60.

Using this calculator: https://spicerparts.com/calculators/...rpm-calculator

Re: Opinions wanted on 3.78 in a Columbia
 

I was just going by what my tach says, maybe its wrong. The engine sounds wound up at that speed.

Re: Opinions wanted on 3.78 in a Columbia
 

Dang. I just sold a nice set 3.78 ring and pinion with the banjo center section for $50 @ Hershey.