Mustang II 8" rear-V6 compared to V8 help

I have a '77 cobra with the 8" rear and 2.79 gears.
I bought a '78 mustang that has a V6 and what looks like a 8" rear.
The doortag says "axle code" 7, which i think is 3.40
I need to know asap if the V6 8" is the same as the V8 8"
I see the driveshaft is the same diameter, except the last 6" of it taper down a bit.
Is the yoke smaller on the v6?
Are the bearings and pinion shaft the same as the v8 8"?

Please anyone with this knowledge please post back.
thanks

The rear end from a 1978 v6 mustang ii
should be the same as a v8 . It is easy to tell . There were two types used one was an integrel build from The back the 8 inch is a remove the diff from trhe front type . If it has a rear cover then it won't work in the V8 car . The 3.40 -1 gears should be a big help over the 2,78-1.

Yes I see they are the same.
I have a issue though, the axles are not round.
The center of 1 axle is 85 thousands out, the other 3 are 37, 39 and 50 thousands out.
The axles seem to be that way from the factory?
I see on the worst one, the machined ends taper down from the splined end and there is a buldge on one side.

Is that cause for alarm?

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Ok I aslo see the V6 driveshaft, (automatic) is a larger diameter than the one in my V8 Cobra.
Does anyone has a description of the v8 shaft?
or a picture?

I hope its not a 4 cylinder driveshaft!

omg this is still on page 1 of the 74-78 section??

Looks like a good cause of rearend ribvation due tot he fact the shafts are off balance. What is your plans for the car? Racing or just driving?

I've seen shafts like that in nearly all rear ends I've pulled apart...
They never vibrated, if yours vibrate then there's another issue I think...