69 C20 trailing arm rear end swap?

[FatherandSon]

The HO 52 4.10 rear end on my 69 C20 with trailing arms suspension is tired. What's my best option for a swap? Who has done one already? So far I have located a replacement HO 52 4.10 and a Dana 60 3.54 from a leaf suspension.
I also have a 12 bolt 3.73 posi from another project but the tube is smaller so I need some input for the easiest way to adapt it to the wider U-bolt holes formed into the trailing arms. I have a basic 350/290hp and TH400. I drive it daily but don't do much hauling since I lowered it 2 1/2 front & 4" rear.

Your input is appreciated!