How long can a single driveshaft be

Hello all,
I have a 55 first series Chevy pickup longbed that I have swaped out the front clip and transplanted a differnt motor and trans, i did a rough measurment and it looks like i am going to need a 67"-70" drive shaft if i am going to keep the long bed, So my question is can this be done? I have been reading that having too long of a drive shaft can be a problem. Any thoughts on a doner vehical that has that long of a shaft.
thanks

 

I have one from a suburban 1/2 ton 2wd, it is almost that long, joint to joint.
I also have one from a delta 98 (bought it for the th400 yoke, $25)
I'll measure and get back to you tonight.

 

A long bed truck can use a single piece driveshaft if everything is done right. Many long bed trucks had two piece driveshafts, though.

Using a long tailshaft transmission helps.

 

i was just told by a shaft shop that 72 inches is the limit, after that it needs to be 2 piece.

 

Some of the early 50s Olds, Cads, and Pontiacs were long driveshafts.

 

lmao....one piece driveshaft in my wife's 08 silverado is 82" long.

 

Here is a question. How does a 2 piece get set up correctly then? What angles to keep a vibration out of it?

 

Copied from the innerwebs...

"Example: Here is the scenario: The transmission points down towards the rear of the vehicle at 5°. The first shaft also points downwards, but at 3°. The operating angle between the transmission and first shaft is 2° (5-3). The second shaft points up towards the rear end at 2°. The operating angle between the first shaft and second shaft is 5° (2+3). Now, we take the first operating angle, and subtract the second one from it. Here, it would be 2-5. This gives us a -3. As I said before, there are no 'negatives', so we ditch the - sign, and we are left with a 3° operating angle that we need to have between the second shaft, and pinion. Since our second shaft points up towards the rear of the vehicle at 2°, this means that our pinion can either point up towards the front of the truck at 1°, OR, it can point down towards the front end at 5°. When the rear end points up, we add to the second shaft angle. When it points down, we subtract. 2+1 = 3, and 5-2 = 3. So either way, we have a 3° operating angle, which will put our system into harmony. See the diagram below:"

 

I have a two piece in my caddy, it was hell to get it dialed in, but runs really smooth now. I went from the stock '66 caddy trans to a normal turbo 400 trans, it was about 6 inches shorter, so we went with a two piece.

 

I got one in the garage out of an old MOPAR that's right @ 80".

Its a 4" instead of the more common 3". The allowable length is affected by the diameter of the shaft. A long skinny shaft is going to be more wiggly that a long fat shaft.

 

hell yeah man. THank you. Getting ready to do this on my OT 67 " once was " 4x4 suburban. Again. Thank ouy.

 

I just bought a 1 pc for my 77c10 i put a 700r4 in. 69 1/2" It was out of a 90s chvy truck.

 

Thanks Guys this is some good information, I knew someone here would have run across this by now.

 

F-85 Was this shaft one of the Big Alum. Ones?

 

I think you mean the Pontiac tempest "rope" shaft used from 61-63.

 

The one from the suburban is 3" at the yoke and flares up to 4" for the most part, then back down to 3 at the yoke.

no, he's talking TO F-85, not referencing the F-85 car. 90+ chevy truck does have the big aluminum driveshaft.

 

The max length for having one made may depend more on the capacity of the shops equipment where you inquired rather than what will actually work well.

I've never had a problem or issues with a two piece driveshaft and have one in my 71 GMC that I have swapped front halves on a few times during transmission swaps.

Back to the original question there should be a number of drive shafts that will fit or that can be shortened a bit to fit. If you were here we would run down to my buddy's place where he has probably a hundred drive shafts standing in apple bins out behind his shop.

You can cheat a bit by figuring out what U joints you need on the shaft and then going to the O'Reilly web site and plugging in a bit of info on what you have. In your case you would want to plug in the vehicle that the rear end came out of to start.
here is a link to the U joints in my 71 GMC http://www.oreillyauto.com/site/c/d...1305896&forcedVehicle=true&pt=01462&ppt=C0362
If you click on comparability will bring up a list of vehicles that use that ujoint. A long list in this case but it will give a guy a list of possibilities in his driveshaft hunt. Then you will have a pretty good idea of what drive shafts use the same U joints as the rear end you have. It doesn't help to go and buy a driveshaft that is just the right length and then find out that the joints don't match up even with combination joints. You can buy combination joints to make most things work but that is another added expense and also can be an issue on a road trip if you have one go bad and the closest parts houses don't have that joint.

 

As porknbeaner stated above, driveshaft diameter comes into play. A 4" diameter shaft can be made longer since it is more resistant to wobbling than a standard 3" driveshaft. Driveshaft RPM is also a major factor; running 4.10s and 26" tall tires is going to spin the shaft a lot faster than 2.56s with a 28" tall tire at the same vehicle speed.

To answer your question, I've seen some driveshafts at 80+ inches. The one in my wagon is 75" and I don't have any problems with it, but it was custom-built with heavy emphasis on balance.

 

Most driveshaft makers say 72" because that is all the longer their balancers will go to. I work with several of them in my day job (selling Jeep parts) Keith

 

Not exactly one of DeLoreans better design ideas?

 

The olds is 62", the suburban is about 68". Which transmission do you have? As squirrel said, a longer tailshaft might work in your favor, long term.

 

Funny, I had 2 77 C10's with 8' beds, and one had a 2 piece and the other a 1 piece. Both had long shaft th350's. The 1 piece had a 350 in it, and the 2 piece had a 305 in it. The single one is larger in diameter for the bulk of it's length. I honestly can't say why they were different, but they were.
If I had a choice I'd run the 1 piece just to get rid of the bearing and it's drag. If the 2 piece in my 83 goes, I'm going to stick the long single one in it's place. Of course I'd have to clearance things a bit to eliminate bumping into the frame.

 

I personally like the 2 piece in a long bed pickup. My longbed S-10 also had a 2 piece driveshaft.

 

I had a 75 C-10 short box with a two piece drive line. Talking the guy I knew at the dealership, it was because the truck came with a turbo 400. If chevy put in a Turbo 400 they installed a two piece drive line.

 

Thanks for all your replies I need to another hand to hold the tape and get an more acurate measurement and hit the pick-a-part and see if I can find something. Thanks again