Hey guys! Please excuse my ignorance, but I'm a first time Ford owner and I'm trying to figure out how to tell the difference between the Ford C4 and the C6 transmission. And I'm trying to figure out which transmission is in my 70 County Squire with a 390 big block. Again please excuse my ignorance, I'm a long time Chevy mechanic and have always shyed away from those 4 letter words.
Should be a C6. I don't think they put C4s behind big blocks. However, there is a small block version of the C6.
C6 is most likely. The bellhousing is integrated into the case like this: http://www.4x4review.com/Portals/1/OldImages/tech/Top10Trans/c6.jpg The C4 transmission is very unlikely as they didn't bolt them up to the FEs from the factory. There are conversion bellhousing available for FEs, but they are expensive and usually used by drag cars because the C4 is so much lighter than the C6. The C4's bellhousing, case and tailshaft are aluminum and the trans will be much less substantial than a C6 like this: http://www.ford-trucks.com/forums/attachment.php?attachmentid=49352&stc=1&d=1329665999 The last option is a FMX which has an aluminum bellhousing, cast iron body, and aluminum tailshaft. This was used from the mid-60s through the late 70's. I'm not sure if they ever built an FE bellhousing for it, but here is a pic for your reference: http://www.roadkillcustoms.com/hot-rods-rat-rods/media/images/FMX.jpg If you are having a hard time telling by looking up at the trans in the car, follow this link to check by the shape and bolt count on the trans oil pan: http://www.roadkillcustoms.com/hot-...Transmission-Identification.asp#axzz2g08HqKuR
I have a 390 in my wagon backed up by a solid C6 originally put together in 1975. Shifts are crisp and it goes into gear with no waiting. A solid combination along with a good 9" rear end. As I understand it... the C4 is a small block trans for the straight 6 and the little 302 V8. But as was said above... many 302's came with the C6 as well. (Had one in a '69 Mustang I once owned and lament selling to this very day.)
C4's have been around a long time. They went behind 170 c.I. I6s all they way through 351W. The 351C typically received an FMX and the performance 351C got a C6 with a 10" converter and 3000 RPM stall from the factory! The FMX backed up to 351W, 351M, 400 and possibly a couple others while the C6 typicall went behind big blocks. The small-block C6 is actually pretty uncommon and I don't believe it went behind 302s. The 351C shares its bellhousing bolt pattern numerous other engines. You can see a list here: http://en.wikipedia.org/wiki/List_of_Ford_bellhousing_patterns By the way, here is a great link you will want to hang on to if you are trying to identify your Ford engine: http://www.fordification.com/tech/engineID-V8.htm You don't have be an expert, or really even all that good of an observer. Just count the number of bolts on the valve cover and you will know what engine family you are looking at.
