Rear brake lines on an 8 3/4 question...

I recently aquired an 8 3/4 out of a 72 plymouth duster that im working on fitting onto my 66 barracuda. Just yesterday i threw out the lines as they seemed clogged and no fluids ran through them. I bought a new brake hose dorman (for a 72 duster) as well since whoever had it before just cut it off.

My question is this: will that brake hose fit on the current original brake lines underneath my barracuda? Are the sizings different? In addition, the bolt that held that dorman onto the rearend snapped when i tried loosening it. Thankfully it came out very easily and no damage to the thread was done. Anyone know where i can get a new one? Or if the one on the 7 1/4 will work?

Also, underneath now is a 7 1/4 rear. Can anyone guide me to the appropriate shock plates i need?

Is there anything else you guys suggest??

Thanks!! :)
The brake hose should fit. You will need shock plates for 3" axel tube. You will also need new U bolts, 3"