Drive line

[Clovis]

I’m doing a short bed conversion on a 81 Silverado 350/350 combo 10 bolt rear. I’m using the brothers truck kit from holly. my local machine shop says my drive line can not be cut. Can anybody help me figure out what length drive line I will need

 

[nvrenuf]

Any reason given for why your driveshaft cannot be cut down?

 

[SquareRoot]

Find a different shop.

 

[Clovis]

It’s a one piece drive like that is necked down from 3.5in to about 2in on both ends they told me they would have to make a new drive line with my yokes and it would cost more then buying a new one

 

[Ricko1966]

I’m doing a short bed conversion on a 81 Silverado 350/350 combo 10 bolt rear. I’m using the brothers truck kit from holly. my local machine shop says my drive line can not be cut. Can anybody help me figure out what length drive line I will need

You can figure it out yourself, unfortunately you will have to wait until your frames back together and rearend installed. With the car sitting on the ground on all 4 wheels or relatively level with the rear axle tube supported by jackstands. Do not do this with the rear axle hanging,like on a lift or the frame supported on jack stands. Now take a drive shaft yoke and push it into the transmission,until it bottoms,pull it out about 3/4 inch this doesn't have to be exact. Measure center of the yoke you just installed to center of rearend yoke with a tape measure. Then head to your local big salvage yard armed with a tape measure and start looking under stuff and measuring. You will find something the right length(may require a different ujoint) or something that can be shortened. The thing about shortening one, you cut the weld that holds the yoke in place,slip the yoke out,cut the tube,slip the yoke back in and reweld it,actually not a tough job.And if you didn't cut any weights off it will still be balanced. Anyway if you are getting something too long,make sure the area at the yoke is continuous 1 diameter the distance you need to shorten it,plus a little.

 

[SquareRoot]

In that case, it makes sense..I had new ones made recently and asked them to use my yokes. To me they were perfectly good and felt tight. They looked at them and laughed at me and said that junk was worn out. In hindsight, it's cheap to just start from scratch knowing it's all new parts, you don't have to worry about vibration and balance issues and will likely outlast the truck. But, you have to have everything else done and take proper measurements, don't guess and don't do it without weight on the truck, aXLe and trans installed. Carry on.

 

[Grit dog]

Never seen a yoke that “wore out”. Seen some trashed. I’d have been skeptical as well @SquareRoot.
@Clovis ya I thought my long bed c10 was all larger diameter but idk?
If there’s not enough length to support the whole yoke then I suppose they are right.

 

[TotalyHucked]

Honestly I'd try to find a different shop, sounds like they're gonna be difficult.
Only way to do it right is to have the truck on it's weight and measure center to center on the u-joint cap openings. I made some cribbing to get the truck ~1.5ft up in the air (cribbing goes under the wheels), that way the truck is 100% on it's own weight when measuring.

 

[Clovis]

Well truck is back together I have a drive line from a 92 I’m going to try out tomorrow i have seen some post saying they fit. The cut process when more smooth then I was expecting also flipped the axle today went pretty smooth also.

 

[Ricko1966]

Accidently found a place to get a driveshaft for you.

1981 Chevrolet C10 Driveshaft - OEM Replacement

Quality 1981 Chevrolet C10 Driveshaft. Complete OEM fitment product with u-joints, balanced and ready to fit all 1981 Chevrolet C10 vehicles.

driveshaftstore.com

 

[ChuckN]

Accidently found a place to get a driveshaft for you.

1981 Chevrolet C10 Driveshaft - OEM Replacement

Quality 1981 Chevrolet C10 Driveshaft. Complete OEM fitment product with u-joints, balanced and ready to fit all 1981 Chevrolet C10 vehicles.

driveshaftstore.com

Wow, free shipping even.

 

[SquareRoot]

Wow, free shipping even.

Hopefully not by FedEx. They could destroy an anvil in shipping.

 

[Clovis]

Accidently found a place to get a driveshaft for you.

1981 Chevrolet C10 Driveshaft - OEM Replacement

Quality 1981 Chevrolet C10 Driveshaft. Complete OEM fitment product with u-joints, balanced and ready to fit all 1981 Chevrolet C10 vehicles.

driveshaftstore.com

Thank you! I’m going to order it. Just for anyone wondering the 92 Chevy drive shaft was the correct length u-joint to u-joint but the length of the splined yoke is about 1 3/4 longer for the 700r4 and the yoke on the differential side is a little to wide. It could work if you find the right u-joints and swap the splined yokes

 

[Clovis]

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Looks a little funny with the different colored bed but At least it fits. Looks pretty straight too.