rover420

From what i hear the c4 is a straightforward swap just a little crossmemberrelocating. The only thing i was woundering ifthere was any other way than balencing to find out if the the flexplate i have is a 50oz balancedflexplate or a 28oz one.

I took the flywheel off that was still on theengine and stuck it on a balencer cone i added weight to it till it balenced out then did the same to the flexplate and it worked out whitch was weird cause the guy i got if fromsaid it came out of a 69 or 70cougar. Unless he had a newer block, but i can't get ahold of him.The code on the C4 checks out to be a 69 c4.

irish1

Excerpt from a huge thread on C4s(C4 MONSTER THREAD Edition IIb) too large to post here, if you want more info I'll email the whole thing to you.

2 - Identifying the tranny
Lots of confusion exists here, but there is the early C4, with its .788" 24 spline input shaft. This tranny is inappropriate for all but the mild small block. The pan fill case, introduced in ’65 is considered stronger than the case fill. The later C4 introduced in ’70 with its .839" 26 spline input shaft is considered the heavy duty unit and is the choice of the builders on this site. This basic HD C4 was again redesigned in 1982 with a convertor clutch (that locks up), a deeper bell housing, a unique valve body, a number of other different internals and named the C5. The C5’s superior oiling circuit includes a number of small differences from the C4 making it the preferred setup of the three as you can replace the C5 convertor, bell and valve body with standard C4 units and have a super duty C4. All three versions can be either case-fill or pan fill.
Of course there are a couple bastard versions you may run across. The ‘65-’66 “green dot” shift pattern valve body versions are in a ton of Mustangs. A good upgrade is to retrofit a ‘67-’69 valve body to those units. A rarer one is the ’70 26 spline version which was a one-year deal. Both ends of the input shaft have 26 splines which was changed to 26 on the converter end and 24 on the forward clutch housing end for all subsequent years.
So the various versions-
C4 - 64-83
· Case fill 24x24 spline {C4 to C9}
· Case fill 26x26 spline {D0}
· Case fill 26x24 spline {D1 to D9, & E1SP)
· Pan fill 24x24 spline {C5 to C9}
· Pan fill 26x26 spline {D0}
· Pan fill 26x24 spline {D1 to D9}
· C5 - 82-86
· Case fill {E2AP only)
· Pan fill {E2TP only}
Bellhousings of course come in several versions. Case fills come with bells that bolt to the pump while pan fills come with bells that bolt to the case. C5 bells are deeper than either of the C4 versions. Most of the time, the case fills use the 157 tooth flywheel and the pan fills use the 164 tooth, but there are exceptions. The best tip I've seen to ID them is to measure the depth. If the depth is 5 7/8" it is a small bell 157t, if it is 6 1/4 is regular bell 164t and if it is 7" it is a c5 bell 164t.

rover420

Is there anywhere in that thread that u have explain anything else about the diffrent flexplates and how to tell if it's a 28oz or 50oz flexplate. I would get it balanced but i'm just woundering if i'mwasting a hour drive and 80 bucks.

irish1

Would you like me to mail it to you?

rover420

ya, if u wouldn't mind. Thanks

irish1

Sent, hope it has useful info, its one of those I grabbed but have not read fully yet.