351c FMX in 1970 mustang grande

[elucero]

I just purchased a 351c and transmission for $300. I was told it was a C4. It came out of a 74 Torino. But the Transmission is an FMX. The question is will the FMX fit in a 1970 mustang and will it require any modifications. I have a 302 and C4 in the car now but both need to be rebuilt. Will the 351 fit on the C4?

Thanks

 

[elucero]

Looks like I can answer my own question.

CJ Pony Parts and the Mustangs Unlimited lists the same transmisson mount for all 56-73 transmissions. It also lists the same motor mounts for 66-70 V8 and 69-72 351W & 351C.

It also lists 65-70 V8's with 51 inch drive shafts. 71-73 V8's with 52 inch.

So It looks like it will fit with no mounting problems.

 

[Max Power]

I think all 351 equipped vehicles in 69-70 came with FMX transmissions.

Edit: Those with automatics, anyway....

 

[ForceFed70]

My 70 grande has a factory FMX....

 

[bnickel]

pretty much all ford cars with either 351w or 351c had the fmx up until the early 80's. there are some exceptions that had the c6 but those are few and far between. even the early 400m used the fmx too. the fmx is a pretty stout tranny and gets a bad rap a lot of the time, but it is generally undeserved.

 

[Cupid]

Huh?

I'm 100% positive that I have a c-6. Now I need to figure out if it is not factory installed.... *sigh*. I thought I noticed that the driveshaft look sorta newish. Since the tranny is swapable, does the same driveshaft apply? I guess this would solidify my speculation that somebody swapped it out.

 

[351carlo]

I have a 70 Grande with a 351c and an FMX. Or well it had an FMX. They are a great trans and mine held up to a lot of abuse, just a little heavier and not much aftermarket support.

Oh and your C6... it's a one piece transmission full aluminum casing?

 

[bnickel]

I'm 100% positive that I have a c-6. Now I need to figure out if it is not factory installed.... *sigh*. I thought I noticed that the driveshaft look sorta newish. Since the tranny is swapable, does the same driveshaft apply? I guess this would solidify my speculation that somebody swapped it out.

i guarantee that if the 351c 2v was factory installed the original trans was an FMX. the ONLY 351 powered mustangs that got a c6 were the 71-73 351c 4v cars and not even all of those got the c6.

 

[Cupid]

I have a 70 Grande with a 351c and an FMX. Or well it had an FMX. They are a great trans and mine held up to a lot of abuse, just a little heavier and not much aftermarket support.

Oh and your C6... it's a one piece transmission full aluminum casing?

Yup! That was a key indication. Oh and just looking at the pan.

 

[elucero]

Me and my son took the engine and transmission out of the car today.

Here are some pictures of the car and the engine removal.

http://www.allfordmustangs.com/photopost/showgallery.php/cat/500/ppuser/36066

 

[elucero]

I got the motor and checked the transmission. The mount is 2 inches different between the C4 and the FMX. So to use the same drive shaft a different crossmember would be needed.

I got this information from CJ Pony parts on part numbers for the cross members.

C-4 & Manual is C7ZZ-6A023-D
FMX C9ZZ-6A023-A

I'm also trying to verify which heads this engine has. No part numbers on the outside of the heads. I pulled the valve covers off and the only number is 4A3.

Any help would be appreciated.

Ed

 

[jes72mustang]

There should be either a 2 or a 4 cast into the upper left corner of the head as looking at it from the side of the car to tell you if you have the v2 or v4 heads.

There are two version of the v4 heads thought an I don't think you can tell the difference without removing them. The casting number for the heads is nearly impossible to see without removing the heads.

 

[elucero]

Thanks. Yes the heads do indeed have a 2 on the corner.

 

[Sicarius428]

C6 will fit too. Strong tranny but a bit on the heavy side. My 70 came with a factory C6.
Kevin

 

[GrandeStang73]

Im swapping from a FMX to a C-4 and custom made my own mount out of 1/2" steel. Easy enough really. I prefer C-4 over C-6 because they are smaller and lighter, but a 4-speed toploader will be the best anyday. I had a 351C 2V great motor for low end torque, but i think my 351C BOSS 4V will be alot better when i get the tranny back in.

 

[elucero]

Turns out. The C4 mount is the shape of a C. To fit the FMX all I had to do was flip the mount around so the C was facing the other way. It fit.

This is my Son's first car, a torque motor will better for him.

Ed