Anybody know what length driveshaft I need?

[LXguy]

Hey All

I've got a 318/904/7.25 Dart. I'm replacing the rear with an A body 8-3/4. Stock driveshaft is too long with the new rear end.

Also, how do I know which u joint the 8.75 takes? Rear end has a 489 case if that makes a difference.

Thanks!

Steve

 

[70aarcuda]

8.75 generally take two different u joints...

7260 which is 2 1/8
7290 which is 2 5/8

you are going to have to measure the yoke on your rear end....

 

[demon seed]

You're going to have to measure yoke center to yoke center once you've got the 8 3/4 installed and have a drive shaft shop modify your old shaft. There are to many variables to actually come out and say "this is what your drive shaft length should be".

Terry

 

[LXguy]

Shaft appears to be 52.5" from the center of the u joints.

My yoke measures 3.25" across? What U-joint would that be?

EDIT: A Ford 1310 Fits perfectly.

 

[pettybludart]

I thought all .489,s came with the 7290 u-joint?I,m also going to make my own drive shaft.I have a slant 6 904 going to a 7290 yoke on a .489 8 3/4.It sounds odd but I just got the car and it has all brand new clifford 4bbl. intake,headders,dual exhaust and also a brand new holley 4bbl..I want to try out the motor for a while,then down the road i,ll have a proper V8 shaft made.

 

[LXguy]

I thought all .489,s came with the 7290 u-joint?I,m also going to make my own drive shaft.I have a slant 6 904 going to a 7290 yoke on a .489 8 3/4.It sounds odd but I just got the car and it has all brand new clifford 4bbl. intake,headders,dual exhaust and also a brand new holley 4bbl..I want to try out the motor for a while,then down the road i,ll have a proper V8 shaft made.

Sounds cool. Doing it different is doing it better. LOL!

I've never seen a 7290 that I know of, but this one is bigger than the measurement that was quoted.

 

[JohnRR]

I thought all .489,s came with the 7290 u-joint?I,m also going to make my own drive shaft.I have a slant 6 904 going to a 7290 yoke on a .489 8 3/4.It sounds odd but I just got the car and it has all brand new clifford 4bbl. intake,headders,dual exhaust and also a brand new holley 4bbl..I want to try out the motor for a while,then down the road i,ll have a proper V8 shaft made.

no they don't , the engine in front of the rear dictates the u joint size .

 

[JohnRR]

Shaft appears to be 52.5" from the center of the u joints.

My yoke measures 3.25" across? What U-joint would that be?

EDIT: A Ford 1310 Fits perfectly.

you need to check which one you have , I think the ford 1310 is close to the 7290 .

measure the inside to inside distance between the caps .

 

[crackedback]

This might help you identify what you have.
http://www.dennysdriveshaft.com/img/File/how_to_measure_diagrams/b.html

IIRC the 1310/1350 joint uses a tab outside the cap or snap rings to locate it. If the yoke has neither, it's not a 1310 joint.

7260/7290's use a snap ring on the cap to locate in the yokes.

The driveshaft you need is about 52" C to C (51.96") according to the service manual.

 

[LXguy]

Wow. Thanks for the help!

Maybe my Chinese tape measure is off by half an inch. LOL!

Anyone know how strong these stock driveshafts are? I'm trying to decide between buying a used stocker or having an aluminum one built.

Steve