3 Speed To 4 Speed

Posted By: Dago Red

3 Speed To 4 Speed - 12/28/12 02:43 AM

I only have one stick car and it's already a 4 speed.

A local garage owner is helping his cousin upgrade a 71 Duster. Nice car.

A s/b stroker and an 8 3/4 but it has a three speed (floor mounted)

How difficult to change over to a tried and true Ma Mopar 4 speed and what parts will they need? (A clutch and new flywheel will be necessary too)

These guys a mechanically sharp, they just haven't done any early Mopar stuff. They even tossed out a Chevy guy who bad-mouthed the build. Ya gotta like that!

Pretty please, don't launch into a sales pitch about aftermarket 5 speeds or overdrive automatics.

I'm asking here because this is where the sharp razors hang out.

Thanks in advance.

Posted By: 64dodge572

Re: 3 Speed To 4 Speed - 12/28/12 03:03 AM

If it is a V8 3-speed, all you would need is the 4-speed, shifter & linkage, as the bellhousing will be dual bolt pattern to accept either transmission. We can supply whatever you need.

Wayne

Posted By: ScottSmith_Harms

Re: 3 Speed To 4 Speed - 12/28/12 04:15 AM

Hi Wayne,

Is there a better 3 speed shifter setup available (shifter mech, rods, linkage, etc.) that is a direct replacment for a stock 70-74 A-body unit? Maybe one that the stock shifter handle will work with? The factory mechanisms are sort of junkie.

Posted By: therocks

Re: 3 Speed To 4 Speed - 12/28/12 11:58 AM

Scott I think Hurst made one.I have a 3 speed that someone stuck in the 65 B sedan I had.It has a Hurst shifter.Seems to be a tight shifter.Been sitting on the garage floor for probally 10 years.Seem no one wants 3 speed trannys.Rocky

Posted By: Dago Red

Re: 3 Speed To 4 Speed - 12/28/12 04:42 PM

Wayne is the 4 speed an improvement, strength wise, or is the 3 speed stout enough?

It seems unusual to me to have a 340 A-body with an 8 3/4 with a 3 speed between the pair.

Posted By: Dodge-N-Shelby

Re: 3 Speed To 4 Speed - 12/28/12 04:57 PM

A few years ago, I picked up a 72 Demon, 340, 3 speed with 3.23s. I swapped in a set of 3.55s and it was a real fun car on the street. 340 was stock, never messed with too. Of course, I didn't have the eqivalent set up with a 4 speed to compare it to either, but it was still a manual!

Posted By: Rhinodart

Re: 3 Speed To 4 Speed - 12/28/12 05:01 PM

A friend in high school had a brother who owned a 71 Demon with a 340, 3-speed, and 3.91 gears, it was the quickest street package in town! Stoplight to stoplight he couldn't be beat!

I thing the combination of the 3-speed gear spacing and the 3.91's was ideal.

Posted By: ScottSmith_Harms

Re: 3 Speed To 4 Speed - 12/28/12 05:25 PM

Quote:

I thing the combination of the 3-speed gear spacing and the 3.91's was ideal.

I'll let you know

Posted By: 64dodge572

Re: 3 Speed To 4 Speed - 12/28/12 05:27 PM

Scott--no, there is no Hurst replacement shifter for the 3-speed available, I am sure there was years ago, but since Hurst was purchased by B & M there is no info available on a part number to go by to possibly find a NOS package somewhere. The 4-speed would be an improvement over the 3-speed, better splits and stronger, although the A230 3-speeds were pretty tough as well.

Wayne

Posted By: ScottSmith_Harms

Re: 3 Speed To 4 Speed - 12/28/12 05:31 PM

Yea that's what I thought Wayne but figured if one existed you'd know about it. Keep me in mind if you stumble accross anything I can use. I am going to run a Passon 5 speed eventually but I need to get my car put together so while I'm waiting I'm gonna run the 3 speed because that was what originally came in it.

*Have you noticed any differences between the shifter mech/shifter/linkage setups for a /6 3 speed trans and a v8 3 speed trans? Speaking 1970-71 A-body.

Posted By: 64dodge572

Re: 3 Speed To 4 Speed - 12/28/12 05:37 PM

Quote:

Yea that's what I thought Wayne but figured if one existed you'd know about it. Keep me in mind if you stumble accross anything I can use. I am going to run a Passon 5 speed eventually but I need to get my car put together so while I'm waiting I'm gonna run the 3 speed because that was what originally came in it.

*Have you noticed any differences between the shifter mech/shifter/linkage setups for a /6 3 speed trans and a v8 3 speed trans? Speaking 1970-71 A-body.

Scott--No, its the same crap. Wayne

Posted By: mikeysmopars

Re: 3 Speed To 4 Speed - 12/28/12 05:50 PM

If you do change to the 4 speed The drive line is going to need to be shortened.

Posted By: 696pack

Re: 3 Speed To 4 Speed - 12/29/12 03:25 AM

Quote:

A friend in high school had a brother who owned a 71 Demon with a 340, 3-speed, and 3.91 gears, it was the quickest street package in town! Stoplight to stoplight he couldn't be beat! I thing the combination of the 3-speed gear spacing and the 3.91's was ideal.

The three speed has a good gear spread for racing. We sold a new 70 340 Challenger (A66) with that 3 speed and it hauled the mail through the 1/4.

Posted By: Supercuda

Re: 3 Speed To 4 Speed - 12/29/12 03:28 AM

Quote:

If you do change to the 4 speed The drive line is going to need to be shortened.

It shouldn't need shortening with an A body A833. Maybe a different yoke though, depending on the A833 in question.

Posted By: Commando1

Re: 3 Speed To 4 Speed - 12/29/12 03:04 PM

Quote:

Scott--no, there is no Hurst replacement shifter for the 3-speed available...

Why won't the Hurst Universal 3 speed shifter work?

Posted By: Anonymous

Re: 3 Speed To 4 Speed - 12/29/12 04:18 PM

Quote:

It seems unusual to me to have a 340 A-body with an 8 3/4 with a 3 speed between the pair.

It was actually pretty common, as the 3-speed didn't get an insurance surcharge like the 4-speed did.

Quote:

If you do change to the 4 speed The drive line is going to need to be shortened.

No, I've done this conversion a couple of times; the (all-synchro) three-speed manual trans is the same length as the 4-speed manual, so the driveshaft length is the same. As I recall, you do have to change the front yoke, though, as the 3-speed has a 904 sized/splined output shaft, while almost all 4-speeds have the 727 sized/splined output shaft.

Posted By: Dodgeguy101

Re: 3 Speed To 4 Speed - 12/30/12 12:41 AM

Quote:

Quote:

If you do change to the 4 speed The drive line is going to need to be shortened.

It shouldn't need shortening with an A body A833. Maybe a different yoke though, depending on the A833 in question. [/quote

I agree, did the 3 speed to 4 speed swap in a 71 Demon with a 318, all that was needed was a different yoke.

Posted By: Pale_Roader

Re: 3 Speed To 4 Speed - 01/02/13 01:50 PM

While we're discussing 3 and 4-speeds...

Would a 70 E-body 3-speed in a 6-cyl car be the same as the 3-speed in a 340 car? Did they make different 230's in the same year like they did with 833's?

You could get a 383-2bbl with a 230 3-speed, could you not? Between those and 340's thats gotta be a pretty solid transmission.