Look at the tranny oil pan. C4's and C5's were rectangular in shape and had 11 bolts; C3's are also rectangular, but had a "bump" in them. They had 13 bolts.
Check out this link for what I'm talking about: http://www.crankshaftcoalition.com/wiki/Transmission_identification#C3.2FC4.2FC5.2FC6.2FAOD_series_comparison
Best bet is to look on Wagons and V6's. Also, the C4 I pulled was mated to a 2.0 and the bellhousing lines up perfectly with my 2.3. If you're not sure, bring your flexplate from your car and line it up to the transmission you're looking to purchase.
Hope this helps.

-Steve 



Edit: Well I feel like an idiot, looking at the picture in the link both types appear to have a small bump in the oil pan. Go by the number of pan bolts.

The '74 Pinto's had the only true 2.3/C-4 bellhousing. --- CORRECTION SEE SECOND POST DOWN ---  Earlier (C-4) Pinto's had the 2.0 bellhousing that requires special dowel inserts to work (on a 2.3). I'm not sure what year the C-4 was initially used, but '74 was the last year.  After that my understanding is they went to the less desirable C-3.

 FYI, the rare '74 only C-4 bellhousings sells for over $150.  I had a perfectly functional 2.0/C-4  transmission I couldn't get rid of (all be it with a cracked bell housing - but still a C-4). Eventually when I put a 700R4 in my Studebaker I returned the C-4 (as a core) to Pick A Part for all of $18.  I've got a 86,000 mile 2.0 that might end up in similar fate.  Seems like I can't find takers..., then once their gone..., a need pops up.

Tom

Thank you for the correction (and sorry for the error).  Somewhere on the turbo 2.3 sites I had read that it was the '74 Pinto only. It seemed to be a common statement thus I assumed correct. Perhaps they were referring to the first year a direct bolt-on C-4/2.3 bell was available???

I found this: http://mmerlinn.tripod.com/trans/fdc4f/fd6c4bhm.htm and it does seem to show other applications. They also have a great I.D (pictures) display also. Regardless it still seems to be rare as s the statement below attests.   Wish I had known. When I see them, I pull them, and sell them on Ebay.  I've probably passed up more than I'd like to know. Other than crawling under the car is there an easier reference (numbers)?   Tom

"Here's an important side note.... the best way to get a C4 transmission to bolt to a Ford 2.3 engine is to find a special bell housing which Ford put on a very limited number of cars in the 70's.  It's possible to use a C4 bell housing from a 2.0 engine car, but that requires some special stepped dowel pins.  Not a big deal.  But, the easiest choice is the C4/2.3 bell housing (D42F 7976 AA).  It's possible to find these old bell housings, but they are not lying around in every junkyard.  They are not easy to find.  Because of their limited numbers and the demand for these, I've seen them selling on Ebay for $200-$300!" 

" It's possible to find these old bell housings, but they are not lying around in every junkyard.  They are not easy to find. "

One of mine came from the local Pick N Pull,(80) and another from a pile of bellhousings
thrown out behind a trans rebuilders shop.
The whole C4 from the 80 was less than 45.00(1/2 price weekend) and the
other was a "bring me one for weight(gave them a SBF bell).


Sometimes you just get lucky.

Paul LeDuc(owner of TF) makes the step dowels to use a 2.0 bell.

OK guys I really appreciate all the help. Heres what I have. Although none of my cars have a c-4 according to the door info sticker. I have a complete early 2.0 and automatic transmission setting in storage. That transmission has an 11 bolt pan. So from what I am reading this is a c-4 and the bell will also bolt to a 2.3. Right? And if so I'm not getting where the step dowels are used, what and where is TF owned by Paul LuDuc who supplies these step dowels. I am also wondering if I'm going to be able to use the same cross member. Do you know?  Thanks again,   Tom

Here is a thread on TF I helped research.
Maybe it will help.


Here is some info I've been working on with Racer99:

C-3..8-pump bolts..13-pan bolts
C-4..7-pump bolts..11-pan bolts

C3 modulator=sticks out toward passenger side
C4 modulator=sticks out toward rear of car

C3 produced 74-87
C4 produced 64-81

The following part #s are ATP brand for
reference only.
C3:
Front pump gasket fg151
front pump seal fo123
front pump bushing fb38
ext housing gasket fg154
ext hiusing seal fo122
ext housing bushing fb37
trans filter b46
shift improver kit fk4
modulator fx219
pan gasket fg150
dipstick tube o ring so33
intermediate band fx195

C4:
Front pump gasket fg138
front pump seal ko1
frt pump bushing kb1
ext housing gasket fg104(except bronco)
ext housing seal ho9(cars,73up trks)
fo185(64-72 trk)
ext housing bushing fb12
intermediate band fx209(snap)
shift improver kit fk3(73-81)
trans filter b39/b31/b32/b43/b59
Here are a few more
C3 flywheel 80 and earlier z108(3 bolt)
C3 81 up and C4 z109(4 bolt)

I did verify that the late(81 up) C3 flex is the same as a 2.3 C4 flex as I checked my new ATP Z109 against the factory flex in the Merkur.
See ya, Chris

Paul