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FMX to C6 conversion
I have a friend with a C6 laying around the garage ready to install. What would I need to put it in my Mach one. It started life mated to a 351C so I suspect the work would be minimal. What is a fair price for it? Is there any value in the swap considering I think I may need to overhaul my FMX.

Bright lime 72 Mach 1 with 351C 4V, with summit 600 carb(have a Holley too), Edelbrock dual-plane manifold, Hooker headers, 3 inch exhaust with flowmasters, 17 inch Eleanor wheels, FMX tranny, A/C, P/S, front disks and 350 rear gear. Drive it to work every day.
I did my first c6 swap when I was young and didn't know much about cars. Here is what I remember.

The cross member worked fine. No issues.
The trans cover is different
Drive shaft length was different (I think I had to make it shorter, it has been a while)
The linkage for mine was different. It turns out they used different linkage for different cars. I was able to adapt it to make it work by adding some length to it. The 'right' way would have been to get one from a mustang and swap it in. This means a tear down to some degree. This is the part I would check out closely. I 'believe' that some of the c6 had reverse linkages and that would be a nightmare. This is only from some internet reading and I do not have real world knowledge to confirm this.
Different torque converter.
I don't think I had to swap flex plates but someone will correct me.
No issues with the starter.
I never got the kick down hooked up but I think I messed that up during a previous carb swap, not during the transmission swap.

73 Convertible - 351C/4V CC heads/4bolt/forged flat tops/comp 270/rhodes/mallory unilite/tri-power/hookers/glasspacks/c6/3.50 limited slip/Gear Vendors/Global West sub frames, strut rods and shelby style traction bars/ Rear sway bar/tilt steering (not original)

Pics of modifications included in:
My son swapped his FMX, that needed rebuilt for a "free" C-6 when he was in HS. They rebuilt the C6 in shop class, and it has never shifter right.
However, this was for a 70 Cougar, 351W. The drive shaft was shortened 1 inch, the floor shifter required an adapter to work. (I Think that is the biggest reason the thing never shifts right.)
The FMX has gotten a bad rep over the years for not being a "performance" transmission, but they are very capable if built right. A decent shift kit, and the appropriate torque converter for what ever cam you have, and they will put up with a LOT of abuse. The C-6 is just a horsepower hog...Bigger, heavier, lots of parasitic loss.
Unless you still have everything to put the C6 back in, if the FMX is well fitted and everything for it works, I would be hard pressed to go the C6.
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