Trying to change an fmx to c-4

FasterThenU72 · Nov 2, 2004

I have a 72 fastback. It has a 302 in it with an fmx behind it. i wanted to dump the fmx for a c4, so i went a picked one up from my buddies 66 fairlane sport coupe with a 289 in it. Well it turns out that the c4 bellhousing doesnt line up with the 302 bolt pattern and it also doesnt have a big enough diameter to fit around the plate. What do i do? i dont think anyone makes an adapter for it, cause i called another buddy and he said that ford specially made my 302 for that specific trans (fmx), so like i said i doubt anyone makes an adapter. but hey im looking for help and any ideas so shoot away......

Ronstang · Nov 2, 2004

Sounds like you have a C4 from an early small inline 6 cylinder. They do not share the same bolt pattern as a small block. Even a bellhousing change (which is possible) is not suggested since that C4 is weaker than the ones that came behind small blocks....so basically you need a whole new transmission, unless you can rebuild it and change out the weaker 6 cylinder parts for V8 parts. This is of course assuming you have a 6 cyinder tranny as I suspect from the description yuo gave.

slackr · Nov 2, 2004

The early 289's had a different bellhousing pattern (5 bolts instead of 6 I thought but there was a different bolt pattern even if it was 6), thus the bolt up problem... the FMX usually only had the 164 tooth flywheel .... c4's sometimes came with this or the smaller 157 tooth flywheel, thus the bellhousing size issue. Both problems could be solved w/the right bellhousing.

I cannot speak as to the 6 cyl having a 'weaker' c4 behind them as I do not know if build specs were different, but I do remember the early 289's (and 260's?) having the different bellhousing and maybe even the same as the I6....

JB66 · Nov 2, 2004

Last I knew the FMX was only used behind the 351C in 72. How many bolts hold down each valve cover?

FasterThenU72 · Nov 2, 2004

ok change the year it was a 64 sport coupe, v6 289 and the covers on mine have.....6 bolts

JB66 · Nov 2, 2004

You'll have to find one of the regular C4's from a 302/351. The heavier duty ones have an additional clutch disc in each of the clutch packs as well has all around beefier parts to handle the HP. I had a HD C4 in my 79 LTD behind a 351.

FasterThenU72 · Nov 2, 2004

so are you saying that there is absolutely no way to use that c4 out of the 64 in my 72? cause if there is i need to know how, just for now even, cause you figure the stock 302 my year blows, and i always planned on getting a really good tranny before i built the motor. not to mention the only reason i got the c4 was cause my fmx blew up 2nd gear and the converter is completely shot

slackr · Nov 2, 2004

JB66 said:
Last I knew the FMX was only used behind the 351C in 72. How many bolts hold down each valve cover?

fmx's were used at the very least behind 351w and c from '69 to '73 mustangs.

FasterThenU72 said:
ok change the year it was a 64 sport coupe, v6 289 and the covers on mine have.....6 bolts

v6 289??? I don't remember a v6 289.

Ronstang · Nov 2, 2004

Well, if it is a V8 tranny out of a 64 then it has the 157 tooth flywheel and it sounds like the 72 has a 164 tooth flywheel.....you simply need to put a 157 tooth flywheel of the proper imbalance on the engine.

JB66 · Nov 2, 2004

some tag #'s
66- PCW
70- PEA, PEE, PEF
74- PEE, PEF
75- PEE, PEF
79- PEE, PEF

Tags are usually on the driverside servo cover. Look for cars with 250 cid and up.
Full size and mid sized used the C4.

FasterThenU72 · Nov 2, 2004

ok now im completely confused, the bellhousing says c4 ap 797 6 a, while the front mount says R or B f c4 ap 7a105 a, and then that little round deal on the passanger side says c6 ap 7do27 c what the heck is this suppossed to mean? this is off the 64 c4 just for clarification

Ronstang · Nov 2, 2004

Count the teeth on the flywheel on you car....if it is 164 then you need the 157 toothed one....that simple. No codes need to be deciphered.

FasterThenU72 · Nov 3, 2004

alright well that still leaves the size (depth, length, width) and bolt pattern issue

Ronstang · Nov 3, 2004

FasterThenU72 said:
alright well that still leaves the size (depth, length, width) and bolt pattern issue

All that is fine. I have put a C4 in a 69 Mach 1 in place of the FMX that was there originally. It is a bolt in.

FasterThenU72 · Nov 3, 2004

ok you say that, but i just measured the difference between the bolt holes on the fmx and the c4 and the c4 is almost a 1/2 inch off all around then the ones off of the fmx. but to make sure i tried to mount up the bell housing and it doesnt look like its gonna work. but i do see what youre saying about the plate.... but that would make no difference right because the holes for the bolts dont line up whatso ever.... am i right or wrong?

Ronstang · Nov 3, 2004

All Ford small blocks with 6 bolts holding the tranny to the engine have the same pattern....289/302/351W/351C....the differences are in the size of the flywheels and bellhousings over the years.

FasterThenU72 · Nov 3, 2004

so everybody told me, but im trying to let yall know that when you measure per say the top two holes on the block and the the top two on the c4 bellhousing, there over 3/4 an inch off

FasterThenU72 · Nov 3, 2004

it boggles my mind to think how that would possible work is all....

Ronstang · Nov 3, 2004

I have no idea what parts you are working with then. Facts are facts. Either you are mismeasureing or you have an early inline 6 cylinder C4.

slackr · Nov 3, 2004

The very early 289's (pre 65) were 5 bolt bell housings....
there is a not so informative pic here:
http://www.svs.com/zim/mustang/64engine.html

Trying to change an fmx to c-4

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