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Fmx to C6 swap

Printed From: The Ford Torino Page
Category: Powertrain Specific Forum
Forum Name: Transmissions
Forum Description: For discussion relating to all Ford Transmissions
URL: https://forum.grantorinosport.org/forum_posts.asp?TID=21257
Printed Date: 26-March-2026 at 5:43PM
Software Version: Web Wiz Forums 12.06 - https://www.webwizforums.com


Topic: Fmx to C6 swap
Posted By: tedthemechanic
Subject: Fmx to C6 swap
Date Posted: 13-May-2024 at 1:25AM
Hey guys, Ive swapped out my old 351 w for a newer fresh motor and in the process i decided to install a C6 transmission.  Everything went smoothly until we got to the shifter cable mount. My original trans was an FMX which has the bolt holes for the cable bracket on the back of the bellhousing. The C6 mounting holes are on the side of the bellhousing. We were able to make a bracket to simulate the rear style mounting, the shifter works( i have a column shift) but it feels a little weird, kinda spongy. Does anyone know what bracket or shifter cable I need to convert this over to the proper linkage. Or if anyone has one for sale.  The selector goes to the proper spots on the indicator on the column but i feel like i have to play with it a little to make sure its in the proper gear.  Thanks in advance for any help you guys can give me.
            Ken 


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If it wasn't for the home of the Brave,there would be no land of the Free !



Replies:
Posted By: tedthemechanic
Date Posted: 15-May-2024 at 2:49PM
Update.  Seems like now my shifter is working backward. Does anyone have any suggestions ?  
  Thanks 
 Ken 


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If it wasn't for the home of the Brave,there would be no land of the Free !


Posted By: pyntre
Date Posted: 15-May-2024 at 4:39PM
Turn the car upside down , it’ll
Work perfect then !😂😂

Seriously though  , that’s a quandary!!!
I’ve come to the conclusion I’m rebuilding my Fmx because I don’t want the extra work involved in changing to a c6 !
Especially on my mid 70’s. Mercury that isn’t supported with aftermarket anything . I’ll be watching to see what transpires on your issue !! 


Posted By: Rockatansky
Date Posted: 16-May-2024 at 12:39PM
this is exactly what i warn people about after somebody gives them the idea that transmission swaps are easy. the linkage styles are almost never the same and even when they are, they're not the same enough to work properly. you need to look at the FMX's linkage arm and determine if the cable connected to the arm above or below the shaft. then look at the C6 and find that it's opposite? you can get a universal clamp-on linkage arm for the C6 but be aware, this is where i say they're 'not the same enough' to work properly. the throw distance for each Ford transmission seems to be just different enough that your range selector on the steering column won't match the detents in the transmission, more importantly the precise position the manual valve needs to be in for each range. by chance i just caught a video regarding this the other day, i'll post it below. back to the issue, you'll need to match the throw of the linkage arm to the travel of the cable. something not too many people think about, it's just an arm & a cable right? they're a matched engineered system that is now a bunch of mixed parts and a fabricated bracket. the distance the selector cable moves for each range needs to suit the distance that the linkage arm on the transmission moves the manual valve in the valve body or the transmission is toast

is converting to a floor shifter an option? that'll solve 98% of the problem but you'll still need to verify that the manual valve is happy in the valve body as shown in the video 

BTW, your fabricated bracket needs to at least as strong and sturdy as the OEM linkage set-up, or the transmission is toast











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72 GT Ute
   


Posted By: 72 RS 351
Date Posted: 16-May-2024 at 2:55PM
Ditto, the Ford transmissions often had different versions with the shift lever pointing a much different direction. The floor shift and column shift were usually the option level that determined that. The shift lever is replaceable, often you have to swap to the other kind to get the needed linkage attachment to work. The bracket that mounts the cable is usually a match to the shift lever, so I think generally you use the lever and bracket as a matched set, and then get a cable that works with them. I've only done the C4 to AOD swap myself in my car, I've seen it done in a couple of others in old Mustangs.


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Don
73 Ranchero "Sport 72 front end", floor shift/console, planning EFI 7000 rpm 351 stroker
73 Ranchero GT 351C-4V &4R70W for sale later.
92 Lincoln Mark VII SE GTC, OBDII 347/4R70W


Posted By: Rockatansky
Date Posted: 17-May-2024 at 11:22AM
Originally posted by 72 RS 351 72 RS 351 wrote:

The bracket that mounts the cable is usually a match to the shift lever, so I think generally you use the lever and bracket as a matched set, and then get a cable that works with them.


IIRC having done the same FMX to C6 swap, the transmission mounted cable bracket is FMX specific. the bolt center distance and 'angle of attack' suits only the FMX, the corresponding bracket for the C6 would be completely different. i also bodged the linkage and the shifter stalk was all the down where L1 would be for Park. Great Times! nope, that sucked


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72 GT Ute
   


Posted By: pyntre
Date Posted: 14-July-2025 at 10:22AM
Did you ever get a satisfactory resolution to the problem??
Would like to know what transpired!!!!???’n



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