My 59 f100 has a c6 with a 390 in it currently. Someday it will have a t56 but for now I'm putting in a 4 speed instead of the auto. My problem is that the c6 is way longer then the NP435 so my driveshaft is now to short by a lot. What's my best bet? I assume my only option is a new driveshaft but what's that going to cost?

 

Maybe $120.

 

That cheap? Where would I go to get one?

 

check with the local hot-rod guys & there should be a good local driveshaft shop in your area...........

 

There is one 3 min from my house. But a friend needed new bearing put into his driveline and to install the 3 it was like $50. And they didn't even put the driveshafts back in the truck. That's why im questioning the price of a whole driveshaft.

 

Ask them for an estimate - show them the old driveshaft and the yoke for the 4 speed you are going to use, as well as the length needed. $50 to replace a bearing is not bad.
Another option is finging a junkyard driveshaft that is longer and having it shortened.

 

Makes up new drive shafts, has zillions of used: SoCal Truck Wrecking - 8229 S. Alameda St. - Los Angeles 90001 - 323-587-3144 - Ask for Juan or Marty.

Most autoparts stores & FoMoCo sell driveshaft center supports as kits. Includes bearing/shims/brackets/U-shaped rubber support.