3spd. To 4 spd swap

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Zaydenspapa
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3spd. To 4 spd swap

Post by Zaydenspapa »

I apologize up front, as I'm sure this has been asked and answered. I have a LM 140hp with 4 spd. That I'd like to put the 4spd in my 1966 conv. With current 3 spd. I'm assuming from research', the shifter is the same, what needs done to make the trans swap?
notched
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Re: 3spd. To 4 spd swap

Post by notched »

If the car is a factory 66 with a 3 speed then using another 66-69 4 speed is a bolt in swap with just readjustment of the shifter as the only things that would need to be changed.
But if the 4 speed is a 65 it needs additional items such as the 65 only transmission mount/cross member, modification to the back up light harness and I believe the 65 style shifter stabilizer.
1966 Corsa turbo
1969 Monza convertible
1987 Buick Grand National
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bbodie52
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Re: 3spd. To 4 spd swap

Post by bbodie52 »

:think: The 1965 transmissions were different than the 1966-1969 transmissions, and as such they also used a different length input shaft between the clutch and the transmission.

the 1966-1969 3-speed an 4-speed transmissions used the same input shafts, with the same length and the same number of splines. The 1964-1965 3-speed and 4-speed used different lengths for their input shafts.

Also, the second page indicates that 1965 differentials have four transmission bolt holes, and that 1966-1969 differentials have six transmission bolt holes. (See the chart and information page from Clark's Corvair Parts below...

:link: http://www.corvair.com/user-cgi/catalog ... ge=TECH-13
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:link: http://www.corvair.com/user-cgi/catalog ... ge=TECH-14
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Brad Bodie
Lake Chatuge, North Carolina
Image 1966 Corvair Corsa Convertible
Ecklund
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Re: 3spd. To 4 spd swap

Post by Ecklund »

As you are intent on swapping the transmission in any event, may I ask if swapping in a five (5) speed transmission would be a reasonable alternative?

For those with experience; would the labor, or cost of labor for the five speed swap be similar to the four speed? Also does the five speed trans cost about the same as a four speed?

Doing the swap just to do the swap may not be worth the expense, time and effort. But as you are already doing the swap maybe a five speed is a good choice.
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bbodie52
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Re: 3spd. To 4 spd swap

Post by bbodie52 »

:whoa: There was a very expensive aftermarket 5-speed transmission conversion unit available. It became so expensive that Clark's Corvair Parts discontinued carrying it (see below)...

:link: http://www.corvair.com/user-cgi/catalog ... N&page=128
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:link: http://aboxer.tripod.com/
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Shift Your Corvair Into Overdrive

With The World's Only 5 speed!


The new AMERICAN BOXER R&D, LLC 5-speed, based on the venerable Borg Warner T-5, is a giant leap forward in getting the most out of your Corvair. From mileage to performance you haven't experienced anything quite like the feeling of shifting your Corvair into overdrive.

You will marvel as you purr along in 5th gear at 60 miles per hour, turning barely 2200 RPM (depending on configuration) compared to 3000 RPM with your current transmission. See the chart for available ratios and how they compare to your stock set up.

The transmission is available as a complete unit and is sold with the custom mounting bracket, shift linkage, and all necessary installation hardware included. You can contact us directly by calling Linn Richardson at (425) 485-9807. Or send inquiries by e-mail to: aboxer@juno.com.

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Greatly Enhance Your Performance

Created by
AMERICAN BOXER R&D, LLC
Corvair Performance Parts Engineering
Brad Bodie
Lake Chatuge, North Carolina
Image 1966 Corvair Corsa Convertible
notched
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Re: 3spd. To 4 spd swap

Post by notched »

Jeez Brad, Don't you read prior posts before you post? You sure waste a lot of band width!
1966 Corsa turbo
1969 Monza convertible
1987 Buick Grand National
notched
Posts: 674
Joined: Wed Jul 25, 2012 8:13 pm
Location: Southern New Jersey

Re: 3spd. To 4 spd swap

Post by notched »

Ecklund wrote: Wed Jun 07, 2017 6:12 am As you are intent on swapping the transmission in any event, may I ask if swapping in a five (5) speed transmission would be a reasonable alternative?

For those with experience; would the labor, or cost of labor for the five speed swap be similar to the four speed? Also does the five speed trans cost about the same as a four speed?

Doing the swap just to do the swap may not be worth the expense, time and effort. But as you are already doing the swap maybe a five speed is a good choice.
There were 18 5 speed gear boxes made by American Boxer LLC. It took almost 18 years to rectify the problems that they had.
Kent Sullivan was closely involved in the development and has one of the gear boxes.Kent stated that there are no plans to produce any more from what he has posted on the other message board
1966 Corsa turbo
1969 Monza convertible
1987 Buick Grand National
Zaydenspapa
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Re: 3spd. To 4 spd swap

Post by Zaydenspapa »

Thanks for all the input. I believe you have answered my question. Sure do appreciate it!!
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