6 vs 8 cyl C4 tranny....any difference?

[mustangprodude]

I have a great deal on a complete '66 C4 tranny. The car was a 6 cyl. Did Ford make a "weaker" C4 just for 6 cyl cars? I want to learn how to rebuild C4's , so I figured this would be a good one to learn with. Heck it's only $50 and comes with the bell housing and N safety switch.

 

[rbohm]

there are differences, but they are things like fewer clutches in the clutch packs, and a smaller accumulator valve. the basic trans is the same.

 

[mustangprodude]

Ok I see. So if I rebuild it then I could get V8 C4 parts and simply upgrade it. Aren't the early C4s weak compared to the later years?

 

[57fairlane]

Ok I see. So if I rebuild it then I could get V8 C4 parts and simply upgrade it. Aren't the early C4s weak compared to the later years?

that is correct. Get a 71 or later c4 if you are worried about power output levels. The best casting is either E2 or E4? It is the casting TCI and PA use for their cores. The splines on the input shaft are 26 (vs 24 on 66-69). A local transmission builder told me the green dot c4s can take up to 350hp then stuff starts to break not to mention the lack of controlling the 2-3 flare.

 

[mustangprodude]

that is correct. Get a 71 or later c4 if you are worried about power output levels. The best casting is either E2 or E4? It is the casting TCI and PA use for their cores. The splines on the input shaft are 26 (vs 24 on 66-69). A local transmission builder told me the green dot c4s can take up to 350hp then stuff starts to break not to mention the lack of controlling the 2-3 flare.

That's good info, thanks!! So even if I did upgrade the clutches/pumps/etc to V8 stuff it still won't handle lots of hp. Did K-codes ever come with a C4?

 

[dennis112]

That's good info, thanks!! So even if I did upgrade the clutches/pumps/etc to V8 stuff it still won't handle lots of hp. Did K-codes ever come with a C4?

They did starting in 66'.

 

[mustangprodude]

They did starting in 66'.

Ok, so I guess it's safe to say that an early V8 C4 could withstand 271 hp.

 

[302 coupe]

I wouldn't bother with an early 6 cyl C4, even for $50. Find a 70-up V8 core to rebuild, it will actually be useful for something. C4's are pretty fun to rebuild, not too hard, just complicated enough to be interesting. Pick up a Haynes manual, they have one that covers C4, C6, and AOD. It has lots of pictures and breaks down the steps well. Go to bulkpart.com to get your parts, they have great prices and good service.