I just pulled the 351C engine from my 1973 Cougar Convertible and discovered the flexplate is different from any I have seen before, it is for a small block C6. Anyone seen one of these before and other than being lighter what else is different about it from the solid flexplate? C6 flexplates on top FMX on bottom
I know there is a difference between the C6 flexplate and the FMX flexplate, but I can't see a difference between the c4 and the c6 flexplate, is there a difference or are they interchangeable?
Just shooting in the dark here ... this question is out of my range. I think I'd be inclined to try any that fit the torque converter bolts. Obviously they all fit the crank. Are they all the same diameter / number of teeth? I think it's possible that the sheet metal plate between the motor and bellhousing locates the starter for the slightly different diameter wheels -- so it's possible you'd have to match one of those to the flexplate.
They are each 164 tooth and the same bolt pattern, and all came from behind 351C engines. I can see difference between the FMX and the other two, but I don't see a difference between the C4 and the C6 flexplate. Does anyone know if there is a difference? Thanks for responding BB.
I can't remember which flexplate I used when I did the 460 swap in my '77 cougar years ago, but the 460 originally had a c-6 behind it and the 400 in the cougar was an fmx, regardless I do remember it was a direct bolt up though.
The bolt patterns are the same but the depth of the surface are different between the FMX and the C6, the FMX surface seats closer to the engine and starter while the surface of the c6 flexplate seats further back closer to the transmission. The question still stand as what if any difference is there between the C6 flexplate and the C4 flexplate?
I don't quite understand that chart. I see where a C4 is mentioned, but I don't see where a C6 is mentioned. I know the flexplate on the C6 attached to the 351 Cobra Jet is not the same as a normal C6, but where and what is the difference between the C4 flexplate and the normal C6 164 tooth count flexplates if there is any difference? The flexplate on the upper step on the right side is the C6 flexplate from my 1973 Cougar Convertible and the Silver one to the left of the Cougar Flexplate is also off of a C6 but looks identical to the Flexplate from my C4 on my 1973 Ranchero 500 behind a 351C. Being that I have 7 cars that have variations of 351C engines and either C4 or c6 transmissions behind them, I really would like to know what if there are differences between the flexplates for these transmissions.
It looks to me like the C4 Flywheel per the IPC is C5AZ 6375 T, and the non-CJ C6 Flexplate is D1ZZ 6375 A. You have all the information on this that I have with the capture from the IPC. If you are absolutley convinced they are the same, run it. I don't know.
I am not convinced, that is why I am asking, I want to make sure that I am using the correct flexplate with the correct transmission. I do not see on any of the flexplates a part I.D. number so how would I tell them apart?
When I pulled the Flexplate from the '73 Cougar with 351C and C6 there was not a "load spreader" spacer where it bolted to the crank, but when I removed the Flexplate from the '73 Ranchero with 351C and C4 transmission there was a "load spreader" spacer where the bolts mount the flexplate to the Transmission. Should there always be one of these mounted with the flexplate no matter which Flexplate or Transmission or is this item only needed on the C4 and the FMX installation? The spacer I am referring to can be seen on the center of the two lower flexplates. I also am still not clear if the C4 and C6 flexplates are interchangable. The ones I have look the same except for the fact that the C4 was installed with that "load spreader? spacer while the C6 was not.
I am still getting mixed information on these Flexplates. I have contacted several parts suppliers and transmission shops and received different answers from all of them. Some suppliers show the FMX and the C4 are the same while others state that the C6 and C4 are the same and not the FMX and yet another states that all three interchange. If the C6 and the C4 are not the same than the flexplate that was on my '73 Ranchero 500 was incorrect and might have been the source of the vibrations. I really could use some help on this from someone who really knows these transmissions.
Trikar, C4 and C6 are the same with exceptions bell housing 157 or 164 teeth, small bell or big. I have pulled a few originals and found no torque plate on some, what that means ask ford? As long as it bolts to the converter and is externally balanced 28oz and 164 teeth good to go, but I would put a torque plate on it, cheap insurance. FMX, have no idea...
Kevin the "wrong" C4/C6 flex plate would not have caused the vibration. the difference if any would be in tq.converter bolt circle. now if it has the wrong balance that could have been the problem.
Torque Converters are neutral balance, if it bolts to the plate, the plate is what balances the engine/trans...
yuo CJ I was talking about the "flex plate" balance so roll you eyes back in to your head! The converter reference was about bolt circle..
Cool, but just read what you wrote, didn't make sense, the converter has no reference, either yes or no unlike the flex plate...
All of the flexplates that I have are 164 teeth and all will bolt up to torque converters that I have(c6,c4,FMX) the only difference that I can see is the depth of the surface of the FMX flexplate is different from the depth of surface of both the C6 and the C4 flexplates that I removed. AutoZone shows one flexplate for both the C4 and the FMX, Jeg shows one for the C6 and a different one for the C4, and PAW shows one for C6 and C4 and nothing for the FMX. ALL being 164 tooth count. The transmission shops have told me three different opinions, one saying they're all different, one saying the FMX and C4 are the same and the C6 is different, one saying they are all the same.
