1970 Longhorn DriveShaft??

[quikcam]

I bought a 1970 Longhorn which had a gear vendors overdrive unit installed in it. Therefore the rear section of the driveshaft had been modified. I am in the process of putting it back stock. I have the fwd part of the two piece driveshaft but don't know exactly what length rear section I need. Does anyone know what will interchange with the one I need? Are all long bed truck the same rear section and the front section is the part that is different or am I stuck with finding one from another longhorn??

Help.

[kwmech]

Your best bet would be to go to a drive shaft machine shop and have one built with new joints, carrier bearing and have it balanced. Mis-matching a bunch of parts from the wrecking yard is looking for a headache. The rear piece at the diff should not have changed when the original owner put in the OD. Unless they did something out of the ordinary

[quikcam]

when he installed the gear vendors unit the front part of the two piece was removed and the rear section was modified. All I have is the original front part. The overdrive unit bolted to the rear of the 350 turbo and added about a foot in length. so basically I have a one piece drive shaft that is too short for my application and don't know what length I need to use with my original front section of the two piece driveshaft. like you said probably end up at a driveshaft place paying out the nose for a new unit...

[kwmech]

Sounds kind of weird they way they did it. Usually the rear section stays the same and the front piece is either set aside (for changing back later) or shortened. You'll have to talk to a shop and have them tell you where they want your measurements taken from. Too bad your not in Northern Calif. My son-in-law builds drive lines all day long

[Steven R]

Whats your plans for the overdrive unit and all its related components? I have a stock 71 longhorn that I am restoring and would like to try a overdrive unit. (fyi I will be keeping all my original parts to put back to original if needed)

[kwmech]

Thinking about it. I don't think I've ever seen a T350 in a longhorn. Always a 4 speed or a T400

[WarMonger]

I can measure mine and let you know the lengths. I have a 69 Longhorn

[quikcam]

I really appreciate you guys chiming in on this. I really would appreciate WarMonger if you would measure your driveshafts. Please let me know the lengths on both the fwd and rear one. I believe the front one i have is the original but never can be sure since the original owner passed and i got it from the estate and it was in the back of the truck when i went to get it. I am not sure what was in the truck originally except that it was a 350 engine truck. The transmission now is a 350 turbo. Here it is in all its glory.

[randy500]

I think all the rear driveshaft's of equal model and style are the same length...
It's the front shaft that changes as the crossmember that mounts the carrier bearing is in the same location for a given wheelbase and style of rear springs.

BTW, are you selling the gear vendors unit and if so what is the condition and price?

[brad_man_72]

I can't say this enough. Measure YOUR truck.
I have no idea why they would move the carrier bearing mount and shorten the rear shaft. Modifying the front shaft would have been the only way to do it right.
Call a drive shaft shop, give them measurements from your truck, see what they can do for you.
Even if you are able to throw some mismatch of 50 year old parts together it will at the very least need to be rebalanced and will probably need to be completely rebuilt.... so you have to go to the drive shaft shop anyways, it doesn't hurt to see if they can help you before you waste weeks looking for parts that might not work.

I am a bit biased because I've been building drive shafts for almost a decade, I've pretty much seen it all. I always feel bad when people spend a bunch of time and money on junk they can't use.

[WarMonger]

ok, i climbed under oscar the grouch and this is what I got. bare in mind its dark, just me with a flashlight and tape measure and it was kind of scary outside. front shaft is about 35" from center of u-joints. Rear is about 43-1/2" from center of u-joints. I have a 350 trans and motor. everything is stock on Oscar.