I have a 67 mustang with a 200ci inline 6, with a c4 transmission and obviously a 7" rear. is there a difference in length of the driveshaft from a 289 hooked up to a c4 with a 8" rear?

basically: is it length or strength? or both?

 

The C4 driveshaft (except for 64 & early 65) was the same diameter with the same U-joints as the V8. However, the differential was a different size, meaning the 200 shaft was longer than the 289.

 

so how much needs to get cut?

 

I stressed over this for a while and finally got my answer.

I have a '66 coupe 6 cyl. w/auto and 7.25" rear that I'm converting to 302 w/T-5 and 8" rear. I planned to use the 6 cyl. driveshaft and had already put in new u-joints. After installing the engine/trans and lining up the z-bar linkage, I put in the driveshaft and was pleased that it had about 1" of play, so it was about perfect.

Others have had to have them cut. So, you're really going to have to measure and compare. But like said, there is not a strenght difference.

 

thanks a lot, i guess i just have to wait and see when i pull it all

 

Did a 6 to 302 conversion on my sons 67. Swaped in a 82 302 with a C-4 and an 8" rear from a 66 mustang.
The original 6 cyl driveshaft fit with about 1" before it bottomed out in the trans, good enough for me.

Go to it

 

i couldn't use my old driveshaft. the rear (differential side) had tiny 1210 u-joints for which you can't (and don't want) a conversion. i guess it's what 2+2 meant with early style