U joint ?

[rb70]

How do I tell if I have the 7260 or 7290 style ujoints?

8 3/4 - 3.23 gears

I searched and could not find where anyone specified a diameter for big yokes, versuses small yokes.

[Chryco Psycho]

7260 is 2.125 inside the ears
7290 is 2.625 inside the ears

[rb70]

Thanks!

So the 8 3/4 rearend came with both types of ujoints?

[Katfish]

[rb70]

Why would I want/need to do this conversion?

[Moparal]

Why would I want/need to do this conversion?

You tell us, it is your question. Is something not right?  Dana 60 is a 7290

[rb70]

You tell us, it is your question. Is something not right?  Dana 60 is a 7290

What??
I was responding to Kat and why I need the conversion ujoints.

[Bullitt-]

You would only need the conversion joint if you had changed some part, like the rear end, & had mismatched sized yokes...if their the same size just get the appropriate sized replacement.

[sadil340]

Actually my 340 car has the 7260 to 7290 conversion joint for the slip yoke and it is the factory part. I think it's because the 8 3/4 rear has the large 7290 joint so both ends of the driveshaft have the same large joint. Since it is a small block the trans slip yoke uses the smaller 7260 joint hence the need to covert the small slip yoke to the large driveshaft.

[Alaskan_TA]

The conversion joint was never a factory part as far as I know? 

Some 1970 340 cars (AARs & T/As included) used the small joint in front & the big one in the rear.

[sadil340]

The conversion joint was never a factory part as far as I know? 

Some 1970 340 cars (AARs & T/As included) used the small joint in front & the big one in the rear.

You could be right Barry, I just don't remember anyone changing out the front joint.