A few questions

[OldRedFord]

1st,

The C6 I have came out of a 80s F-series truck.

The transmission end of the drive shaft needs to slide onto the shaft on the transmission witch is 1 3/8" dia 31 or 32 spline, and then on the axle end needs to have whatever size U joint the 9" from our erea trucks accept.

Soo....whats gona be my best option for a doner drive shaft? Or will I be better off with a custom one? Or is that expensive?

Next is, what size U joints fit the yoke on the 9", and where can I get new U bolts for the yoke? Mine are long gone.

[AlleyCat]

The u-joints in later trucks are larger than those used in bumps.You are likely further ahead going the custom shaft route.On the rear you have a couple options.First is to swap the yoke out with one from a later 9" that had the bigger u-joints.Second choice is to use a double size u-joint.A double size joint is wider across one set of caps than the other.The only thing I ever saw them factory installed on was the front drive shaft on highboys.I've used them on low budget swaps where a custom shaft was out of the question.I have some old NAPA part numbers if you need them.

A driveshaft shop should have u-bolts.If not p/m me your address and I'll send some to you.I've got a coffee can full of them.

[OldRedFord]

So what would be the best route to go to get a drive shaft made? And is that pricey?

Since I will race this truck at times, I think it will be worth upgrading to a bigger yoke then.

[AlleyCat]

Check the yellow pages in your area for a driveshaft shop.If you don't have any luck with that I'd suggest looking for a parts store that handles parts for heavy trucks.If they don't make driveshafts chances are good they can give you the name of someone who does.Broken shafts in big trucks are fairly common.

I can't give you any idea on price. It's been awhile since I've had one made for a pickup.

If you are going to race it the bigger yoke would be a good upgrade.

[cdherman]

I had one done in KC recently for $200 and that included new U-joints. (the ujoints need to be installed during the balancing process).

The conversion u-joints that go from 1310 (old size ford u-joint, common in 60s to early70's) to the larger 1330, these are available. Check ebay or if you can get a parts number, locally as well. But if you are having a new drive shaft done, then may as well make sure you have the same size u-joint on both sides.

Be careful about swapping the pinion yoke on the 9" rear. There is a crush sleeve in there and if you screw it up, you'll not get many more miles out of the old 9".

What kills drivelines is torque, low end, low RPM pulling, grinding torque. So if that's what you are going to be delivering to the driveshaft, then the larger 1330 ujoint is better. If your engine is developing 500 hp, but at 7000 rpm, then the smaller u-joint will probably still hold up. Likewise, large tires and low number rear ratios have the same effect. So a 2.70 rear will tear up u-joints much worse than a 4.11. Big tires are hard to spin, so there is more strain on the driveline.