Weight difference between C4 and FMX

I havent used it yet, but i have an FMX trans behind the 351 cleveland i want to chuck in my model A project.
I understand these transmisions are heavy, but does anyone know by how much are they heavier than the c4?

 

Im not a transmission rebuilder but as a Ford guy:
The FMX is made of cast iron.
It breaks when its behind engines with a lot of torque.
It breaks when you install a shift kit. [does not like high fluid pressure]
C4's are plentyfull.
Thats my 2 cents but it probably worth less.
Matt

 

Define torque,
I run a FMX with shiftkit, connected to a 351c, (you know the one with the torque) and I never had any issues.
I believe the weight difference between a FMX and a C4 is around 70 lbs.
I would run the FMX/351C combo in the Model A, don't overcomplicate things.

 

The C4 is alot lighter (based on what you all are saying about the FMX) than the FMX. I can lift one on my own and I'm not a strong guy.

 

FMX-stronger, heavier,larger bellhousing,uses more HP, hard to break

C4-weaker, lighter,smaller bellhousing,uses less HP,easier to break

In Australia, FMXs copped a floggin for decades, and with the 351C/FMX combo......the valves will go long before the FMX.

therefore.....for drag racing seriously, get a superbuiltup C4

......for a street car, use the FMX that you ALREADY GOT, get it serviced professionally, and one day when it breaks, post on here again

Oh,sorry BRO!

I just noticed that you're in Noo Zeeland....USE the FMX 800%
FMXs were in all those XYs and big fat XCs and FMXs were un-frikkin-breakable !!

 

I have an FMX in my 69 Ranchero GT, 351W 4 barrel.. Anyway, I used to tow cars EVERYWHERE with it, and an 1800 # car trailer.
Never had any trans issues. The brakes, even though disc, were not enough to be safe on long grades, so I got a bigger truck. I used it like that for 7 or 8 years, until I parked it to restore.

I would stand by the FMX any day.

 

Father has an fmx currently in his 66 f100 that has gone through 2 302's a 351w and is about to have a rebuilt 351w dropped in the truck. But we are switching to an aod with this engine swap for the overdrive.

 

Zipper, I am afraid that you will be very dissapointed in the AOD, they will not hold up.

 

The FMX IS NOT a performance trans.
It has a shift pattern/throw that is not compatable with most aftermarket shifters, its heavy, obsolete ( in the BAD way...) and not a lot of good parts exist for it.
It will hold up fine, in a cruiser, but the c-4 is FAR superior.
It has a large aftermarket, it is light, it takes less to turn it. They live behind Big Blocks, if prepared right.
It is VERY easy to build/rebuild.
And, still easy to find. A post '68 unit ( I think that was the year...) can be manually shifted.
There is no good reason to use an FMX other than you have one that works fine, and you are not going to ask alot from it. ( which I see is the case!)
I, myself, think that the 70 lbs. is enough reason alone...

 

I think it's about 70-90 pounds difference like others have said. I can wag around a C-4 but have to use something to pick up a FMX. If a C-4 is an option for you I would go with it. The C-4 is lighter, easier and cheaper to rebuild without problems. If they are working ok they both do alright but if I was starting from scratch and setting up for something it would be a C-4. FMX is an old-style design transmission, C-4 is modern-style and less problematic in the long run. I would rather rebuild 2 C-4s than one FMX. If you need a heavier-duty transmission get a C-6. Just my 2 cents.

 

That's ALL true......in America

Maybe NOT so freely available in New Zealand.

 

Cheers for the info and advice.
I see that the general concensis is that they're not the end of the world to be runnling. So since i already have the fmx, along with all the bits that go with it, (im assuming the c4 would require a different converter, flexi plate, starter and driveshaft yoke) ill probably end up running it.
cheers again.

 

In response to Dirty Thirty. Take at youtube look at John Feistrizer (Hoosier Hurricane). Y Block with a supercharger pulling the front wheels off the ground time after time. You are wrong about the shifter choices as you are mostly confusing the Cruiseomatic( green dot) with the FMX. The Fmx is a very strong transmission as it combines internal C6 and small case parts with a very beefy cast iron case to withstand the beating of any stock engine Ford produced. In stock form these transmissions can take up 500 hp ( correct me if i am wrong ). There is nothing wrong with these transmissions as i would prefer them over the C4 any day. Again correct me if I am wrong but I have never heard of a C4 behind a big block unless you are referring to a C6 which would make sense. And to finish my thoughts here... everyone always talks about weight. "if" you only run track what difference is 70 pounds going to make? Hoosier Hurricane's Ford with a very heavy Yblock and a cast iron transmission meant nothing. Here is one more thought. I have never found it hard to find a FMX. Everywhere I look I find one. They are always on craigslist and Ebay. Heck some people give the FMX away for free when they don't know what they have. Ford did a great transmission from 1968-1981 and was placed on many high performance Cars and Trucks. Not trying to cause any enemy's here but i have done a ton of research on these and find them very desirable.

 

running low 12's

 

I hope this clears any doubts one may have with weight and with durability with the FMX. Rock on people!

 

Screw both of them - Buy my Small Bellhousing C6!!!!! At least as strong as the FMX, if not more so, and aluminum case (with ribs) to be lighter like a C4

 

Y Block, I'm not going to argue with anything you say. My memory of weight is 25 years old and based on the green dot cruisomatic. As I remember the bare case was about the same as a TH350 without fluid, or converter. Still think the C4 is a more efficient transmission -less internal drag. As my knees get older I may find myself wanting an automatic some day.
-Dave

 

Had one of those C6 small case and sold it. Solid transmission for sure, no arguments here.

 

Town Sedan, I am only backing up the now Underdog. I forgot one statement from another forum one said. That the C4 was a more modern transmission. Well to some degree yes and that is because of the aftermarket vendors supplying aftermarket kits and stuff for them. Yet the FMX was 4 years newer than the C4. There had to correct the wrong and again stick up with the underdog. It is all in preference to what you or anyone is wants. Go with what you like and be happy. Efficient you say? well maybe true but only by a small percentage seeing that the FMX did not have a rear pump to lose more power like the cruiseomatic did. Either way both FMX and C4 are great transmissions and I own both and have no issues, that being said I just like to read facts and correct the wrong information that gives these transmissions a bad name. And by the way, I hate stick! my first 3 cars were stick and my 64 econoline is stick. I fucking hate doing the work. I am lazy and proud to admit it. I am taking that piece out and putting a C4 behind the 200 inline 6. I'm old and I can't see me shifting gears anymore. I'm over it. AUTOMATIC for the people!

 

Ha! The only time I've wanted an automatic and didn't have one was when I lived in Orange County CA and use to drive the parking lots..., I mean freeways!
-Dave

 

I have been working for ford for more years than I care to admit. I say use the C4. The FMX was a hold over from the original auto trans ford used as the Fx and Mx. Ford could not keep up with demand and would use the FMX to meet production demands. It is a very obsolete ravenaux design while the C4 is a Simson design that is recognized by all American manufacturers as superior. A C4 can easily be built to hold lots of horsepower. I built a C4 for twin brothers many years ago for a drag racing Mustang they have. They have managed to destroy 3 engines but the C4 keeps on working. The FMX had dual valve bodies and tubes that join them together.The tubes are forever leaking and causing internal problems. I don't know how many on here made a living doing transmissions, but I put lots of beans on my plate doing FX to e4od and all in between. And if you want real crap, use a A4LD in something, just have your AAA towing card in your wallet.

 

Geeez, all the guys beating up on the poor FMX....

Keep in mind this was Ford's 'intermediate duty' automatic and was used behind 351Ws, 352/390 FEs, and all Clevelands except for hi-po motors. Keep clean ATF in 'em and adjust the bands every so often and it'll last just fine. The C4 in stock form wasn't up to the power levels of those motors, that's why Ford didn't use it behind them. The C4 can be built to handle the power (due to the racers preferring it) but isn't as beefy as-delivered. The C6 will take the power, but is considerably less efficient which is why it fell out of favor.

And when Ford designed the AOD, it was based off the FMX design for the same reasons...

 

I attended the new product train class when the AOD was introduced. Ford would not deliver an AOD equipped car unless at least one Trans man was certified on it. I was that lucky guy. The instructor explained theory of operation to us and told us the Trans was based on the old ravenaux design similar to the FMX. The whole room gasped and groaned at that announcement., and so did the instructor. A C works vertical well by simple valve body mods, using pickup/van forward and direct clutch
packs halving the band ajustment. I have found a perfect use for an FMX, they will hold a door in position in VERY strong winds! Plus do a fine job of cracking walnuts. Bottom line it is your time and money , believe what you like and spend accordingly. Oil am retired and don't have to put up with anything troublesome, usually.

 

I'm in the C-4 camp, in fact, when I put my FE back together, I will be putting a C-4 behind that as well. I have one of those wonderful FMX's here for sale, if anyone actually wants one of these cast iron clunks. I have had that cast iron turd on craigslist for months for $100 obo, havent even had a response... Cmon you Y-block guys, you need this thing! Its COOL!, Its HAMB approved!!
I also have a small-block bolt pattern C-6 here...

 

I snagged these weights off of a Mustang site, the poster says that they were done on a bathroom scale so they are going to be nominal but they were all done on the same bathroom scale so they will be good for comparison. I hope this helps in your decision.

I do know this for the transmissions that we would normally be using the C4 is the lightest and most versatile of all the automatics.

AOD (without converter or fluid) - 150 lbs
AOD stock torque converter - 34 lbs
C4 (without converter or fluid) - 110 lbs
C4 torque converter - ? lbs
C6 (without converter or fluid) - 140 lbs
C6 torque converter - 30 lbs small block, 31 lbs big block
FMX (without torque converter, unknown fluid level) - 160 lbs
FMX torque converter - 32 lbs
Ford-o-Matic (pre-FMX), cast iron case - 228 lbs

 

California seems to build those long narrow parking lots.

 

FalconGeorge Please post pictures of your C4/FE combo as they never existed and will not work without an Adapter which at that point you might as well do an AOD to get that overdrive and as stated earlier a loose FMX design.

 

SHIT! You mean I wasted $600+ on a bellhousing??!! Guess Id better send it back!
only on the hamb...

 

The FE did come with a C6 one piece aluminum transmission. The C4 is a two piece unit.


Sent from my iPhone using The H.A.M.B. mobile app

 

The C4 becomes not only the lighter of all the mentioned options but also the most versatile. they make bell housings to bolt them to most popular engines. They have actually becomes a popular drag transmission as of late.

By the way that '57 is pulling the perfect on launch wheelie. Good vid.