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C4, C9, C10????

13K views 5 replies 4 participants last post by  gregaust 
#1 ·
whats the difference between these boxes?
Im doin a 250 crossflow turbo build, and everyone seems to use toughened c9s as their box of choice.

How come?
 
#3 ·
C4,5,9 and C10 are all basically the same trans with some differences between them. These are some of the differences:

C4 -
Smaller 24 spline input shaft
Bellhousing and pump share same bolts
trans casing has a 'step' at the front near the bell
filler tube enters case
breather tube exits case near selector lever

C5/C9 -
Larger 26 spline input shaft
Bellhousing and pump share same bolts
trans casing has a 'step' at the front near the bell
filler tube enters case
breather 'cap' in trans extension housing at top
C5 pan has larger capacity than C9 pan

C10 -
Larger 26 spline input shaft
Bellhousing and pump use seperate bolts
trans case has smooth transition to bellhousing mount
filler enters pan
breather 'cap' in trans estension housing

This is how to id them externally. There are minor differences internally so some parts won't interchange, ie valve bodies.
C10 Bellhousing won't fit C4,5 and C9 however C4,5 and C9 bellhousing will fit C10 with longer pump bolts. I believe all C10 bellhousings are designed for the larger 164 tooth flex however C4-C9 housings are available for 164 or 157 tooth flex.

C5,9 and C10 are slightly stronger due to larger input shaft. Beyond that there ain't much difference. Things to watch when swapping is to use the correct bellhousing and converter(24 or 26 spline, 157 or 164 tooth flex compatibility) and also use the correct valve body if swapping
 
#4 ·
Thanks alot greg, that pretty much explained everything. In detail!

Ive got a 87 Fairlane that im working on, and im not sure wat the stock box is. Was it a C-something or will i have to get one from the wreckers to hold the power (180-200rwKW) ???
 
#5 ·
Uhm the C4 came with two versions of the input shaft.

From 1964 through 1969, the C4's made had a 24 spline input shaft and front hub assembly, and with the lower spline count came a slightly smaller diameter on the input shaft. However, the valve bodies in the transmissions are different. The valve bodies fall into 4 different groups. 64-66, 67-70, 70-81, and the Pinto valve body. In 1970, the C4 got an upgrade. The input shaft and front hub were strengthened by enlarging them to 26 spline, increasing the input shaft diameter, but also making its tc and input shaft non-interchangeable with the older 24 spline 64-69 C4's.
 
#6 ·
There was also a 70 version C4 that had a 26 splines on the input shaft both both ends.The input will slip in either way ..
An 87 fairlane is prob a Borg Warner 40...To go to a c4 you'll need to from the flexplate back.The C4 is the same length and same splines on the output shaft.
 
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