If I knew I could get an OD trans (and related parts) locally for some kind of reasonable price I'd be there as soon as they opened next.

But I've been working on engines since I was 12 (well over 50 years), have design, welding, mechanical and other shop skills enough I could build a whole car if I really had to. And altho I'm slow on projects I don't have to run earn a few dollars every day. So I can kill a certain amount of time without ill effects.

It's all relative. Nothing is going to give you a huge improvement in mileage. Nothing. But a combination of careful driving and overdrive should get you as good as many new cars get.

I wouldn't make the swap for gas mileage. Your driving habits are the biggest factor in gas mileage. keep your foot out of it and you'll be alright. I know its hard to keep my foot out of my four speed. and I agree with emsvitil leave the typewriter alone. no new car has anything that cool in it.

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64' Valiant Signet 5.9, 64' Dart 170 moredoor 3.7, 67' A100 3.7, 00' Dakota SLT 4.7

I have zero experience with /6 and automatic trabsmissions. But I just had an experience that seems on point in one way.

Before I got my '65 Valiant out of mothballs, I drove a 1981 Chevy Luv pickup. It has a 4 speed trans and I had no bones to pick with it (altho the emissions control people did).

Today an unusual (and uninteresting) situation prompted me to drive it (very close to the hills of home) a little bit. Apparently I had forgot to top off the rubber band before leaving, because after having driven the /6 a couple months I knew, with no doubt at all, why the Luv required a 4-speed trans. (You don't have to pedal quite as hard between shifts.)

If you're talking non-OD? The /6 does not need 4. Getting back into it after the Luv (big engine option) I felt like I was driving the Luv - with JATO's. Personally I plan to go OD eventually - assuming A-833OD's dont vanish from the face of the Earth in the mean time. In that case, maybe a T5.

Hey slant64, don't be discouraged by cost and difficulty of installation. I know you want better mileage out of this swap, but the auto would likely be better for that. I have a '70 duster with a 225 and auto and have looked into swapping for a manuel tranny, but not for mileage. I wanted a 4 speed for the pure trill and pleasure of it. To control the shifts and to burn the tires of the wheels. I like the feel a manuel gives me, and my suggestion to you would be think of it as something to have fun in and enjoy. I may yet swap to a manuel, in time, but for now I'm staying with the auto because of other projects and because I do enjoy being able to cruse a long time without having to shift. But the bottom line is cars are more than just simple transportation, taxis and buses for that, but for the pleasure of it. Being able to drive where ever we want when we want. Enjoy and be thankful for what you have. God willing you'll have many more projects and cars down the road of life. Start with what you have and go from there, I've read somewhere about slant sixes coming with 3 speed trannys, maybe start with that. Don't let installation scare you, I just replaced the whole front suspension and it was my first time doing that ever and it was not easy. But I had the tools and I had the will, if you truly want to do this than do it, you can do great thing's if you try. Have a project like this as " I'm really going to enjoy this" kind of mentality and all the blood, sweat, tears, and money you pore out on it will be worth far more than how much fuel you may or may not save.

Having just posted what I did about the 4 speed I'm a bit puzzled by the above,

If you want a 4 speed because the shifter looks nice and you like working through the gears that's obviously your choice. But I don't undestand what about a 4 speed will help you burn rubber. The ability to burn rubber comes from two things, power and gearing, right? According to articles here the best first gear ratio you will get from a 4 speed is 3.09. If 3 speeds came as low as 3.22 where is the 4 speed rubber burning advantage? What am I missing?

Thanks

I find that with a stock slant six it's not as easy to spin the wheels with a automatic as it is with a manuel tranny, no matter the gearing. And I said 3 speed because that was what I read, I didn't see anything about a slant six coming with a 4 speed. So I don't know if they did or not.

Uhh yes the old tach it up as high as it will turn and dump the clutch method.
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Buy Vapormatic
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Kawasaki kr350

I know people love to mention the gear vendors external od, BUT do they even make them for the cable shift bt torqueflites. A couple years back I looked into them and they said they had no plans to make them for the early transmissions. With a burnt exhaust valve on cylinder 1 and points and a bad parts store reman carb I get around 17-18 mpg in my 65 valiant with 225/904 that's not too shabby in my book.

And I hate to be a spoil sport but there is a 4 speed article on the home page. There is also a good article on 4 speed over at bigblockdart.com

I wasn't referring to auto vs stick, rather:
Maybe 4-speeds DO burn rubber better than 3-speeds. I don't try either.

Thanks